System and method for comparative analysis of textual documents

ABSTRACT

A system and method are presented for the comparative analysis of textual documents. In an exemplary embodiment of the present invention the method includes accessing two or more documents, performing a linguistic analysis on each document, outputting a quantified representation of a semantic content of each document, and comparing the quantified representations using a defined metric. In exemplary embodiments of the present invention such a metric can measure relative semantic closeness or distance of two documents. In exemplary embodiments of the present invention the semantic content of a document can be expressed as a semantic vector. The format of a semantic vector is flexible, and in exemplary embodiments of the present invention it and any metric used to operate on it can be adapted and optimized to the type and/or domain of documents being analyzed and the goals of the comparison.

TECHNICAL FIELD

The present invention relates to the application of artificialintelligence techniques to automatically identify documents and otherwritten materials with unique semantic content. More particularly, thepresent invention relates to a system and method for the comparativeanalysis of textual documents by creating and comparing semanticvectors.

BACKGROUND INFORMATION

Globally, industries are experiencing a significant increase in theamount of unstructured information, especially textual. This fact issupported by reports from various market research firms, such as therecent finding that the amount of text-based data alone will grow toover 800 terabytes by the year 2004. It has also been recentlydetermined that between 80-90% of all information on the Internet andstored within corporate networks is unstructured. Finally, it has beennoted that the amount of unstructured data in large corporations tendsto double every two months.

Thus, the volume of extant textual data is growing exponentially.Because this data can contain a significant amount of business-criticalinformation, there is a growing need for some type of automated meansfor processing this data, such that the value buried in it can beextracted. Ideally, such a method would involve natural languageprocessing systems and methods. One such potential method is the abilityto compare and contrast two or more documents at the semantic level, todetect similarities of meaning or content between them as well asidentify specific concepts which may be of interest. While a group ofhuman reviewers or researchers could easily perform such a task, giventhe sheer volume and wide variety of subject matter created by evenmedium size businesses, it would tend to be complex and time consuming.In most large businesses, such a task would require a dedicateddepartment whose cost would generally not be economically justifiable.

What is thus needed in the art is an automated system and method for thenatural language processing of textual data so as to discover (i)valuable content contained within such data; and (ii) mutualsimilarities or divergences between or among two or more documents. Sucha system and method could then generate reports of the results of suchprocessing in one or more forms readily useable by humans.

SUMMARY OF THE INVENTION

A system and method are presented for the comparative analysis oftextual documents. In an exemplary embodiment of the present inventionthe method includes accessing two or more documents, performing alinguistic analysis on each document, outputting a quantifiedrepresentation of a semantic content of each document, and comparing thequantified representations using a defined metric. In exemplaryembodiments of the present invention such a metric can measure relativesemantic closeness or distance of two documents. In exemplaryembodiments of the present invention the semantic content of a documentcan be expressed as a semantic vector. The format of a semantic vectoris flexible, and in exemplary embodiments of the present invention itand any metric used to operate on it can be adapted and optimized to thetype and/or domain of documents being analyzed and the goals of thecomparison.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an exemplary conceptual taxonomy of computationallinguistics highlighting sentence analysis;

FIG. 2 illustrates an exemplary syntactic analysis according to anexemplary embodiment of the present invention;

FIG. 3 illustrates example ambiguities at the syntactic level, thusmotivating semantic analysis according to an exemplary embodiment of thepresent invention;

FIG. 4 illustrates an exemplary semantic net according to an exemplaryembodiment of the present invention;

FIG. 5 illustrates an exemplary hierarchical and weighted representationof the information contained in the semantic net of FIG. 4 according toan exemplary embodiment of the present invention;

FIG. 6 illustrates an exemplary semantic vector according to anexemplary embodiment of the present invention;

FIG. 7 illustrates an exemplary process by which documents with uniquesemantic content are identified according to an exemplary embodiment ofthe present invention;

FIG. 8 is an exemplary process flow diagram for semantic vector creationaccording to an exemplary embodiment of the present invention; and

FIG. 9 is an exemplary process flow diagram for automatic documentsearch and processing according to an exemplary embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention facilitates the comparative analysis of thesemantic content of textual documents. In so doing a system and methodare presented for automatically processing the semantic content of adocument quantitatively to extract a representation of the document'ssemantic content in a form that can be machine processed. The disclosedmethod facilitates a text corpus being automatically read, processed andcompared to any other text corpus to determine the semantic “distance”(i.e., some convenient numeric measure of similarity in meaning) of onedocument from another.

Various text analysis tools and techniques provide capabilities in theareas of syntactic, semantic and statistical analysis of textualdocuments. In exemplary embodiments of the present invention one or moreof these tools can be used to extract semantic content from documentswhich are to be comparatively analyzed. A brief description of thesetools follows.

Text-Mining

In exemplary embodiments of the present invention textual documents areaccessed, automatically read line by line, and subjected to text miningto extract their semantic content. Text-mining can include a variety ofcomputational linguistic techniques such as, for example, a syntacticanalysis to extract a number of tokens, followed by a semantic analysisto discover relationships between such tokens. The results oftext-mining can be, for example, presented as or more “semantic nets”associated with a document. As described below, a semantic net can beeasily converted into a “semantic vector” which can be easily used as aninput to a computational algorithm. As described below, a semantic netcan be easily converted to a semantic vector. Alternatively, text-miningresults can be presented as simple lists of unique words and theirfrequencies, words and their synonyms, phrases, etc. Moreover, becauselists and synonym mappings do not provide information related to thesemantic context of the words and phrases which are automatically foundsemantic nets can often be more useful. Thus, because semantic netsrelate words and/or phrases to other words and/or phrases in theirrespective contexts, often in seemingly non-intuitive manners, asemantic net can be a preferred choice for such output.

All text-mining approaches are either based on the theories ofcomputational linguistics (such as, for example, syntactic and semanticanalysis) or statistics (such as, for example, Bayesian, Markov Chainsetc.). Text-mining is thus a set of different capabilities that canperform different functions. For example, Information Extractioninvolves identifying key concepts and extracting them into a data base;Categorization involves grouping multiple documents into pre-definedsets based on their degrees of similarities; and Navigation involvesproviding tools that allow the reader to rapidly navigate through adocument by “jumping” from concept to concept. In comparative documentanalysis, what is needed is to conceptually quantify the content of adocument for comparison purposes. Thus, in exemplary embodiments of thepresent invention semantic nets (and thus semantic vectors) are a wisechoice, where the conceptual contents of two documents needs to bejuxtaposed and compared in a quantitative manner. To illustrate suchexemplary embodiments, the basics of text-mining are first nextdiscussed.

Text-mining involves looking for patterns in natural language texts.Text-mining can be defined as the process of analyzing a text corpus toextract information from it for particular purposes. A text corpus canbe any quantity of text. For purposes of illustration, what will oftenbe referred to is a textual “document.” This term is to be understood inits most expansive sense, and is therefore understood to include anyquantity of text in any format that can be subjected to linguisticanalysis.

The goal of text-mining is information discovery. Unlike numericalanalysis techniques such as, for example, data-mining, that operate onstructured data, text-mining deals with the analysis of text-based data.It is recognized that a complete understanding of natural language text,although a long-standing goal of computer science, is not immediatelyattainable. Thus text-mining focuses on extracting a relatively smallamount of information from documents with high reliability. Suchextracted information could be, for example, the author, title and dateof a publication, letter or article, the acronyms defined in a document,or the articles mentioned in a bibliography.

Text-mining is based on multiple technologies, including computationallinguistics, other artificial intelligence techniques, patternrecognition, statistics and information retrieval. In exemplaryembodiments of the present invention documents can be processed viasentence analysis, a subcategory of computational linguistics. This willnext be described with reference to FIGS. 1-3.

Generally, computational linguistics is understood to be the study anddevelopment of computer algorithms for natural language understandingand natural language generation. With reference to FIG. 1, an exemplaryhierarchical division of the field is presented. Computationallinguistics 110 can be divided into Language Analysis 120 and LanguageGeneration 130. The semantic analysis of textual documents is concernedwith language analysis techniques. Language Analysis 120 itself can bedivided into Discourse and Dialog Structure 140 (useful, for example, toproperly divide multiple simultaneous conversations, such as in Internetchat room monitoring applications) and Sentence Analysis 150, which isthe most useful technology in the context of the present invention.

Sentence Analysis 150 is further divided into two parts, SyntacticAnalysis 151 and Semantic Analysis 152. FIG. 2 illustrates an example ofsyntax analysis. Syntactic analysis is concerned with determining thestructure of a sentence, and the generation of a parse tree using agrammar. Thus, in FIG. 2, a sentence 210 “Mary eats cheese” is dividedinto a subject 220 (“Mary” 221) and a verb phrase 230 (“eats cheese”241, 251). The verb phrase 230 is further divisible into a verb 240(“eats” 241) and an object 250 (“cheese” 251). While this simplesentence is relatively unambiguous, more complex sentences often arenot. Ambiguity at the syntactic level can be resolved via semanticanalysis, as depicted in FIG. 3.

With reference to FIG. 3, the semantic possibilities of the sentence “Isaw the man in the park with a telescope” 300 are illustrated. Using asimilar syntax analysis as depicted in FIG. 2, there can be found asubject “I” and a verb phrase “saw the man in the park with atelescope.” The verb is obviously “saw.” The semantic ambiguity lies indetermining the object, and turns on what exactly the prepositionalphrase “with a telescope” modifies. This phrase could modify the verb“saw”, as depicted in frame 310, denoting that the subject used atelescope to see the man in the park. Or, alternatively, as depicted inframes 320 and 330, the phrase could modify “man” and refer either tothe man being near a telescope or actually holding a telescope, thedifference turning on the semantic sense of the preposition “with.”These ambiguities can, for example, be resolved in a semantic analysis,which can, for example, not only capture the linguistic “tokens” orconcept-words, but can also discover their meaning, in terms of therelationships between them.

Multiple techniques can be used in semantic analysis. One such method,for example, is “deep parsing”, where in addition to analyzing a targetsentence as illustrated above (shallow parsing) sentences and paragraphsbefore and after the target sentence can be considered. Thus, in theexemplary sentence of FIG. 3, it could be, for example, that theobserver has already been associated with a telescope (such as by thestatement “he carried the telescope to the roof top”), thus implyingthat the observer was in possession of a telescope—and thus that theobserver was the person who looked through a telescope at the man in thepark, allowing the conclusion that frame 310 correctly depicts themeaning of the sentence.

It is generally accepted in the computational linguistics community thatorganizational information tends to be 20% data and 80% text. Textualanalysis tools can be thus used to potentially extract the valueinherent in the 80% of the information repository which is textual. Theinformation extracted by text-mining can be in the form of basicfeatures such as, for example, names, locations, or products, and therelationships among those features, such as, for example, the relationbetween a company and a given person, such as, for example, the factthat John Doe is the President of Company XYZ, or that Richard Roe isthe head of the Overseas Marketing Division of Alpha Corporation. Thislevel of information extraction can be far more powerful then simplyimplementing key word searches, because the extracted information isbased on the context within the document, and not simply upon itssyntax. As a result the extracted information can reflect the meaning,or semantic content, of a given document.

In exemplary embodiments of the present invention, semantic data can beobtained from a document using feature extraction, which a type oftext-mining. Table I below illustrates an exemplary document andexemplary information that can be extracted from it in this way. Theextracted information can be used, for example, to develop knowledgenetworks (i.e., a linked network of features), to populate databases forsubsequent analysis, or for mutual comparison. TABLE I FeatureExtraction Example DOCUMENT EXTRACTED INFORMATION Profits at Canada'ssix big banks Event: Profits topped C$6 billion topped C$6 billion ($4.4billion) Event: jump in net income in 1996, smashing last year's C$5.2Country: Canada billion ($3.8 billion) record as Entity: Big banksCanadian Imperial Bank of Commerce Organization: Canadian Imperial andNational Bank of Canada Bank of Commerce wrapped up the earnings seasonOrganization: National Bank of Thursday. The six big banks each Canadareported a double-digit jump in Date: Earnings season net income for acombined profit Date: Fiscal 1996 of C$6.26 billion ($4.6 billion) infiscal 1996, which ended on October 31.

With reference to Table 1, software has been used to automaticallyextract the various semantically significant entities and events fromthe document and to present them by general category using knowntechniques. Such techniques typically rely on syntactic analysis, andextract the definition of each constant (e.g., nouns) using dictionariesand taxonomies.

As noted, text-mining is based on multiple techniques, and generallyincludes shallow and deep parsing. In shallow parsing, text analysis islimited to a single document (e.g., “Mary Eats Cheese” in FIG. 2). Asingle sentence is analyzed, and nouns, verbs and other parts of speechare discovered along with their mutual associations. For example, in thesentence “Mary eats cheese, but Bob eats apples”, Mary is associatedwith “cheese” and Bob is associated with “apples”, and the action is“eating” for both Bob and Mary.

On the other hand, deep parsing involves textual analysis that canresolve the ambiguities which are inherent in most shallow parsingtechniques. For instance, in the above example, it is not explicit whattype of cheese Mary ate. Thus, deep parsing involves processinginformation in sentences before and after the target sentence toestablish the context and help resolve ambiguities. For example, if anarticle is talking about cheese production in Switzerland, and Mary isdescribed as being an American tourist in Zurich, it could be concludedthat Mary ate Swiss cheese. As with most artificial intelligencetechniques, deep parsing is not guaranteed to produce the correctanswer, as Mary could have actually purchased and eaten American cheesein Zurich, but the first assertion is seen as more plausible.

The example cited above is based on heuristics and other associations(e.g., Zurich is in Switzerland, and Swiss implies an association withSwitzerland, and thus with Zurich). A more linguistic example would bethe following: “Bob and Jim were driving up north. Jim was tired, so Bobtook the wheel. He was going to fast and got a speeding ticket.” Fromthe target last sentence it is unclear who got the ticket. However, “he”got the ticket is indicated in the sentence (shallow parsing), and thelast reference to a male subject was to Bob, so “He” in the lastsentence can be concluded ot refer to “Bob.”

Linguistic Analysis

As noted above, text-mining includes a variety of techniques. Inexemplary embodiments of the present invention text-mining can beimplemented via a linguistic analysis using to known techniques.Linguistic analysis, as used herein, comprises two stages. Syntacticanalysis and semantic analysis. Syntactic analysis, as is known in theart, involves recognizing the tokens (e.g., words and numbers) in a textthrough the detection and use of characters such as spaces, commas, tabsetc. For example, first, after a syntactical analysis of a document, asystem according to an exemplary embodiment of the present inventionwould have acquired a sequential list of the tokens present in thedocument. Second, for example, given the tokens' constructs recognizedas described above, semantic analysis rules could be applied to furtheranalyze the document. As noted, semantic analysis rules can, forexample, look for keywords as well as concepts and relationships.

Thus, in exemplary embodiments of the present invention, a dictionary aswell as syntactic rules can be initially used to parse information froma document and its accompanying documentation. Subsequently, semanticrules could be applied that consider much more than simply the key wordsand syntax themselves by performing shallow or deep parsing of the text,and considering the relationships among the entities and eventsdescribed in the text. In addition, terms appearing in the documentcould be looked up in a thesaurus for potential synonyms, and antonymsor other linguistic conditions can also be considered as well.

Semantic Nets and Semantic Vectors

As noted above, the output of a linguistic analysis can be, for example,a semantic net. A semantic net is a data structure which reflects theidea that the meaning of a concept comes from its relationship to otherconcepts. In a semantic net information is stored by interconnectingnodes with arcs or arrows, as described more fully below.

A semantic net can be mapped into a set of weighted components. In thisform the mapped semantic net can be compared with similar mappings ofother semantic nets to compare and contrast the information content ofthe documents from which the semantic nets were created.

One format for organizing a mapped semantic net is a semantic vector. Asemantic vector can be constructed from a mapped semantic net, and cancomprise, for example, a number of multidimensional components, eachcomponent having one or more concept values. Each concept value can alsohave a weighting value. In such an exemplary format a semantic vectorcan be conveniently processed by data processing devices such as, forexample, a digital computer.

A collection of semantic vectors created as described above can becompared one with the other to identify documents with unique semanticcontent. This can be accomplished, for example, by defining a metric bywhich the semantic distance between two documents can be calculated. Inan exemplary embodiment of the present invention, a semantic vector canbe created to represent the claims of a given patent. A number ofpatents can be so represented by a corresponding number of semanticvectors for purposes of comparison. representing of various patentclaims can be subtracted from the semantic vector of each of a largenumber of internal documents, thus identifying a handful of internaldocuments that present patenting potential.

The concepts of semantic nets, mapped semantic nets and semantic vectorsare next described with reference to FIGS. 4-6. FIG. 4 illustrates anexemplary semantic net that could be generated from a textual document.The example textual document that was used to generate the semantic netof FIG. 4 is an imaginary letter about the ABC Publishing Corporation ofNew York, N.Y. The semantic content of the letter includes informationabout the industry which the company operates in, when it was founded,who its CEO is, and a recent acquisition that it made involving a musicdownloading website. This information was processed into the exemplarysemantic network depicted in FIG. 4, as next described.

With reference to FIG. 4, the hub or central focus of the semanticnetwork is the company described in the letter, ABC Publishing 400. Anumber of semantic relationships to the company are found at spokesemanating from ABC Publishing 400 as follows. The CEO 401 of the companyis Dave Bookbinder 410. The Industry 402 within which the companyoperates is Media 420, the company was Founded 403 in the year 1962 430,and it made a recent Acquisition 404 of a business entitled Tunes OnLine 440, which is an on-line music downloading service. Tunes On Lineoperates within the music publishing industry and therefore there is asemantic relationship governed by the descriptor Industry 405 betweenTunes On Line 440 and Music Publishing 445. As can be seen from theexemplary semantic net depicted in FIG. 4, each of the arrows representsa functionality or category at a higher level of abstraction, for eachof which there is a definite or specific value to which the arrowpoints. For example, in general a company has a CEO 401, and thespecific CEO of ABC Publishing 400 is Dave Bookbinder 410. In general acompany operates within a particular industry 402 and the specificindustry within which ABC Publishing 400 operates is Media 420. Everycompany was Founded 403 at some time and the specific year in which ABCPublishing 400 was founded is 1962 430. Companies, in the course oftheir business activities, often make Acquisitions 404 and the specificacquisition described in the textual document used as the source of thesemantic net of FIG. 4 is Tunes On Line 440. Products or companies whichare acquired can, obviously, be described by a particular Industry 405,and thus Tunes On Line 440 operates within the Music Publishing 445industry. Thus, a semantic net can be constructed from a central term,in this case the company, and a variety of generic descriptors ofrelationships to that central term. Valuing these relationships are aplurality of specific values, which, as in this example, may themselvesbe the center of semantic sub-nets, as is illustrated by the value“Tunes On Line” 440 and its relational descriptor “Industry” 405,yielding the value “Music Publishing” 445.

FIG. 5 depicts how the information extracted from a document and placedin a semantic net such as illustrated in FIG. 4 can be further organizedaccording to its relative information content within the originaldocument. FIG. 5 is an example of a hierarchical and weighted list ofthe information extracted in the semantic net depicted in FIG. 4. At thetop of the list, and thus seen to have most importance, is the value forthe company, which is the center of the semantic net depicted in FIG. 4.This is, as above, ABC Publishing. Beneath ABC Publishing are the fourgeneric descriptors from FIG. 4. In FIG. 5 these four genericdescriptors each carry a weight, seen as a number in brackets after thegeneric descriptor. The weight assigned to each generic descriptorcorrelates to how important that descriptor or attribute is to thecentral concept of the semantic net, the Company. Thus, the CEOdescriptor is given a weight of 100 (all weights in FIG. 5 are on ascale of 100) because the CEO of a company is often of high importanceto the company.

Further, the specific person who is the CEO in the example weighting ofFIG. 5 is considered of equal importance to the concept of CEO andtherefore also receives a weight of 100. The information as to foundingof the company is given a weight of 90, and the actual year of founding1962 is given a lesser weight, i.e. 65, on the theory that a preciseyear of founding is not that important to the concept of founding of acorporation as other semantic ideas connected with the founding of acorporation may be. The industry in which the company operates is givena weight of 95 because the industry in which a company operates is oftena key piece of information as regards anything relating to the company.The value for the industry in which the company operates is consideredof lesser significance and therefore receives a weight of 55, the lowestweight assigned in the semantic hierarchy of FIG. 5. Finally, the factthat the company made an acquisition is given a weight of 90. Thecompany which was the subject of the acquisition is also seen as havinga rather high information content and is therefore assigned the value88.

It is noted that weights appearing in FIG. 5 were heuristically assignedfor the purposes of illustration. In exemplary embodiments of thepresent invention weight can be assigned using known techniques, whichcan vary in complexity as may be desired or appropriate.

From the hierarchical and weighted representation of the semanticinformation of FIG. 5, a semantic vector can be constructed. FIG. 6depicts such an exemplary semantic vector. This particular semanticvector has five components corresponding to each of the primaryrelationship spokes 401 through 404 which surrounded the central concept“company” in the semantic net of FIG. 4. The first component is thecentral or key concept, “company”, and the remaining four componentscorrespond to the four components 510, 520, 530 and 540 depicted in FIG.5 in the representation. Each of the components of the semantic vectorof FIG. 6 itself has a number of elements. The company component has twoelements, namely the generic category “company” and the specific value“ABC Publishing.” The first component in the exemplary semantic vectorof FIG. 6 has no weighting, because that is the central semantic conceptaround which the entire semantic net was built, as depicted in FIG. 4.The remaining four components do have weights, both for the genericcategory in each component and the particular value within thatcategory, such that a semantic vector can be compared with a semanticvector constructed from other documents. As can be seen in FIG. 6, thesecond component 610 has three elements, “ABC Publishing”, “CEO (100)”,and “Dave Bookbinder (100)”. The third component 620 similarly has threeelements: “ABC Publishing”, “Founded (90)” and “1962 (65).” The fourthcomponent 630, relating to industry, similarly has three elements: “ABCPublishing”, “Industry (95)” and “Media (55)”. Finally, the fifthcomponent 640, relating to acquisitions, has three elements: “ABCPublishing”, “Acquired (90)” and “Tunes On Line (88)”.

As noted, the weighting assigned to elements of the semantic vector wasdone heuristically. In generally, weighting can be done in one of twoways (or via some combination of them). First and simplest, for example,certain key terms or concepts (e.g., CEO, Company) could be pre-weightedin a rule base, based upon the judgment of a domain expert. Second, forexample, weights could be assigned (and subsequently refined) as aresult of characteristics of the corpus being mined. For example, aconcept such as “CEO” could be assigned an initial value of, forexample, 80 and its value could be incremented for each five occurrencesfound in the corpus, up to a value of 100. Likewise, concepts could beassigned higher weights if they are found in conjunction with other keyconcepts, such as, for example, “Chairman and CEO”).

The process of forming a semantic net around a key concept, transformingthat to a hierarchical and weighted representation of its information,and finally processing the hierarchical and weighted representation intoa semantic vector is merely exemplary. As is known in the art of textmining and semantic analysis, there are numerous ways in which toconstruct semantic nets and semantic vectors and, in general, the bestway to implement such tools is data- and/or context-specific. Thus, thetypes of documents that are desired to be compared will, in many ways,determine the semantic analysis which the documents are put to and theway the information extracted by the process is organized.

Assuming there is an optimal application-specific format for expressingthe unique semantic content of documents, analogous to the exemplarysemantic vector of FIG. 6, FIG. 7 illustrates how semantic vectors canbe used to automatically generate useful information for the business.

FIG. 7 illustrates an exemplary process by which documents with uniquesemantic content can be identified. In the example depicted in FIG. 7,Internal Documents 710 can be a number of internal documents generatedfrom various sources within a particular company. None of the internaldocuments are synoptically analyzed or organized by any one departmentor individual within the company, and as a result there is no humanintelligence which can determine which of those internal documents mightcontain information which is valuable intellectual property, and whichat the same time has not been already patented by the company. The otherset of textual documents which can be subjected to comparative analysisare patent claims 720. These can comprise, for example, the various setsof patent claims from either some or all of the then-existing patentportfolio of the company. What is desired to be accomplished in theprocess depicted in FIG. 7 is the comparison of the various patentclaims 720 with each of the internal documents 710 to determine if thereare any internal documents which are so semantically unique or distantfrom each of the sets of patent claims 720 that one or more internaldocuments may be worth further developing into a patent application.This process is depicted at 730, where the semantic vectors of each ofthe internal documents is subtracted from the semantic vectors of eachof the patent claims one by one and, if the resulting semantic vector isof large enough magnitude, a set of semantically unique documents 740(relative to patent claims 720) is generated. Because semantic vectorsare mathematical entities, they can be easily processed by digitalcomputers. Additionally, if they are properly defined, as known in theart, semantic vectors can be automatically generated from the sets ofinternal documents 710 and patent claims 720, respectively. Therefore,there is no requirement of spending the costly human resources to makethe patentability analysis depicted in FIG. 7. This is precisely one ofthe advantages of automatic comparative analysis of textual documentsusing semantic vectors. The results of the process depicted in FIG. 7,as noted, is the set of unique documents 740 which can then be given toa human for analysis as to whether one or more of these semanticallyunique documents should be developed into a patent or other intellectualproperty asset.

Alternatively, another example to which the present invention could beapplied is the inverse of locating documents which are patentable ornovel relative to a first set. Such inverse process involvesautomatically locating documents with a similar semantic content to afirst set. In intellectual property disputes an accused possibleinfringer often desires to know if the patents asserted against it arevalid. If there exists prior art which teaches the invention claimed inthe asserted patent or patents, this is of great defensive use to anaccused infringer. Thus, in exemplary embodiments of the presentinvention a system could automatically search for documents whosesemantic vectors are close to those of a given set of asserted patents.This example is illustrated in detail below with reference to theAppendices.

Additionally, in exemplary embodiments of the present invention thelatter process could be implemented, for example, in a second stage ofthe first. This is because in some contexts simply searching through acorpus of documents and discarding those which have close semanticrelationships to a set of patent claims does not necessarily output“patentable” material. While it can eliminate potential redundancies sothat what is left are documents semantically distant from existing knownpatent claims, it says nothing about their potential“patent-worthiness.” Thus, in exemplary embodiments of the presentinvention the exemplary process depicted in FIG. 7 can have a secondstep that takes the output from the first step and compares it to knownnon-patent-worthy documents; i.e., an exemplary system at this stagelooks for semantic closeness to uninteresting documents. For example, adocument in a corpus that is a press release announcing a new CEO is ofless interest from a patenting perspective than would be a documentdescribing a process for managing a network, and should therefore bediscarded. Thus, in contexts where an exemplary process can operate uponcompletely arbitrary collections of documents rather than constrainingthe corpus to contain only a pre-qualified selection of documents, sucha step could be implemented, for example, to minimize an output set fedto human analysts.

Exemplary Semantic Vector Generation

FIG. 8 depicts an exemplary process flow for generating a semanticvector according to an exemplary embodiment of the present invention.Such process flow can be implemented, as can be any embodiment of thepresent invention, for example, in a software program, in a dedicatedchip, chipset or other hardware configuration, or in any combination ofhardware and software as may be convenient or desirable in a givencontext.

With reference to FIG. 8, an original document in text form 801, can beinput. At 805, the relevant words in document 801 can be, for example,locked based upon a word list in database 830. This process protectsdomain-specific words that should be preserved for subsequent analysis.For example, in the automotive domain, such domain words can include,for example, “Steering”, “Brakes”, “Suspension”, “Fender”, and “Grill.”Such domain words can, for example, be locked via insertion of hiddentags in a document, such as, for example: “<lock> Brakes </lock>.” Thedomain words in database 830 can, for example, be further expanded withsynonyms and word stems as defined, for example, in Thesaurus and WordStems database 850. For example, in a given embodiment “Fender” and“Body Panel” may be synonymous and should be treated identically.Similarly, word stems define different ways of expressing the same word,such as, for example: “Drive”, “Drove” and “Driven.”

At 810 the redundant words in document 801 can be flagged, with theexception that words which were locked at 805 would not be flagged asredundant. Redundant words can, for example, be supplied by a WordExclusion List 840. Such a list can, for example, define words that donot add semantic value to a document, such as, for example, “here”,“and”, “but”, and “if.” Redundant words can, for example, be markedindividually or in groups with hidden tags, such as, for example:“<redundant> if </redundant>” or “<redundant> thus </redundant>” or“<redundant> but when the </redundant>.” Redundant words in WordExclusion List 840 can, for example, be further expanded with synonymsand word stems from Thesaurus and Word Stems database 850.

After processing at 805 and 810, refined document 815 can be generated.Refined document 815 can be identical to 801, except for the fact thatdomain words and redundant words (and their respective extensions) canhave been marked with hidden tags, as described above.

At 820, frequency analysis can be performed on the non-redundant wordsin refined document 815, counting the number of occurrences of eachdomain word. Examples of output from frequency analysis can be, using,for example, a document 801 whose content deals with an automotivedomain, “Steering 18”, “Brake 9”, and “Grill 7.”

At 821 a weight can be assigned to each non-redundant word. Such aweight implies importance or relevance. Weights can be, for example,determined by Word Relevance Rules 860. Examples of such rules can be,for example:

-   -   If a word occurs in the first or last 15% of the document, then        Weight =+5;    -   If a word is a domain word, then Weight =+2;    -   If two domain words are within 5 words of each other, then        Weight =+1 for each word; and    -   If two words are consecutive, then Weight =+1 for each word.

The weightings as assigned by the above example rules are cumulative, soan instance of a word appearing in the first 15% of a document (+5) thatis also a domain word (+2), and is also within five words of anotherdomain word (+1) would have a weight of +8. Or, for example, each keyterm can be given a base weight score, and the above rules or anequivalent used to cumulatively add additional score points. Numerousalternative weighting schemes are thus possible in exemplary embodimentsof the present invention as may be desirable in the context, as afunction of, inter alia, known semantic patterns regarding the type ofdocument and/or the semantic domain(s) within which it falls.

As illustrated above, using a given weighting scheme, differentinstances of the same word can, for example, have different weights. Asdescribed more fully below, such instances can be processed separately,for example, by using the specific frequency and weight information ofeach instance of a word as an input to a semantic distance metric, or,for example, all instances of a given word can be combined into acomposite score for that word, with an overall frequency and a compositeweight. The tradeoff between such options is high resolution anddetailed analysis versus available computing resources and processingtime.

At 825 a tabular output can be generated, listing all of thenon-redundant words, and their associated frequencies and weights ascomputed at 820 and 821. Output 825 may be sorted alphabetically, byfrequency and/or by weight as may be appropriate in given contexts.Output 825 represents a semantic vector for document 801. Such semanticvector can be, for example, further formatted and processed prior tobeing input to a comparison algorithm or process, or can be processedas-is, using algorithms designed to operate on all of its components, asmay be desired in given contexts.

As noted, 830 is a database of domain words, i.e., words which are knownto be important in a given domain or practice. In exemplary embodimentsof the present invention this database can be manually or automaticallygenerated. Automatic generation of domain words 830 can, for example,implemented by analyzing a set of domain documents, and searching forcommonly occurring words not appearing in Word Exclusion List 840.

Word Exclusion List 840 is a database of common words independent ofdomain. These words are those that are necessary for an originaldocument 801 to be readable by humans, but that need not be included forsemantic analysis. Database 840 may also be, for example, manually orautomatically generated. Automatic generation of database 840 caninvolve, for example, statistical analysis of a large set ofdomain-independent documents, and the identification of words that occurwith a high frequency.

As noted, 850 is a database of synonyms (typically domain specific) andword stems. It can, in exemplary embodiments according to the presentinvention, be utilized to extend databases 830 and 840 to words whichare not necessarily listed in those databases.

Word Relevance Rules 860 can be, for example, a rules knowledge-basethat can, for example, determine how the weights assigned to domainwords should be computed. Its rules can be expressed, for example, inIF-THEN form, as illustrated above, and can be implemented via look-uptables or a commercial inference engine (i.e., an expert system). WordRelevance Rules 860 can also benefits from the information in Thesaurusand Word Stems database 850.

Automated Document Search Using Autonomous Software Module (“'Bot”)

In what has been described thus far no mention has been made as to howdocuments which are to be semantically compared with a known set ofdocuments are to be obtained. This can generally be done in a variety ofways, which can, in exemplary embodiments of the present invention, varywith the specific application. For example, in the exemplary embodimentof the present invention depicted in FIG. 7, where the goal is toexamine a set of internal documents 710 for patentable novelty over (andthus for significant semantic distance from) a known set of patentclaims 720, a central directory on a company's network can be set up,for example, where all invention descriptions, white papers, andinventor's, researcher's and/or engineer's notes are deposited. Such anexemplary system could, for example, take every document which has beenstored on that directory and process it according to an exemplaryembodiment of the present invention.

Alternatively, in other exemplary embodiments of the present invention,such as the search for prior art application described in the detailedexample below, where a goal is to locate documents which aresemantically close enough to a set of patents to potentially invalidateone or more of them, there is, in general, a much greater universe ofpotential documents to choose from. Simply having an exemplary systemprocess every possible document it that can find via the Internet,available databases, or other sources would be an inefficient use ofsystem resources.

To accomplish such a goal, human screeners could, for example, searchfor potentially useful documents in an initial cursory screening anddeposit them in a directory. An exemplary system according to thepresent invention could then process those documents. Alternatively, aspecialized computer program could replace the functions of humanscreeners and search through the Internet or other domains for documentsthat satisfy a number of specified conditions. Such conditions could bedesigned, for example, to find documents which are, for example, (i)semantically close to a given set of patents, (ii) semantically distantfrom a set of patent claims, (iii) semantically close to a news story ofinterest, (iv) semantically related to certain ideologies or activities,such as, for example, those of groups under surveillance by authorities,or (v) fitting any semantic criteria of interest in a given context.Such a program can be, for example, an autonomous software moduledesigned to traverse a network.

Such autonomous software modules have been used in the art for a varietyof purposes such as, for example, the discovery of applications residenton servers or work stations, or for the discovery of hardware devices oncomputer networks. Such programs are colloquially known as “robot” or“'bot” programs. Such 'bot or 'bots could be used, in exemplaryembodiments of the present invention, to procure documents for semanticcomparison processing according to an exemplary embodiment of thepresent invention. Such an exemplary process is next described.

In general, two exemplary approaches to implementing a'bot-basedtraversal of a domain are possible. In one, for example, a single 'botcan be instantiated and can traverses a domain one location at a time.At each location, the 'bot's payload can be activated and run tocompletion, at which time the 'bot can move on to the next location inthe domain. This process can continue until there are no more locationsin the domain to discover, at which time the 'bot “dies.” This mode ofoperation is simple and minimally invasive on a given domain.

In an alternate approach, where a domain is hierarchically organized,upon reaching a given level, a 'bot can spawn replicates of itself ateach location on that level. Each replicate (as well as the original'bot) then attempts to discover and spawn a replicate of itself on thenext-lower level of the hierarchy (if any), where the process canrepeat. This mode of operation quickly places a 'bot at every locationin the domain, each having a payload ready to deploy. Improperlyimplemented, this mode can act in a very virus-like manner and can placea considerable strain on the domain's resources if precautions are nottaken.

'Bots have two components: a mechanism for traversing the domain inwhich they explore, and a “payload” that performs some activity at eachpoint in the traversal of the domain. In exemplary embodiments of thepresent invention a traversal mechanism can, for example, have thefollowing characteristics. It can (a) have knowledge of its currentlocation in the domain (e.g., an IP address on a network or a directoryname in a file system); (b) have knowledge of where it has been to bothaid in determining the next location to visit, and to avoid visitingalready-visited locations (unless this behavior is desired), (c) knowhow to detect other locations in the domain (such as, for example, bypinging on an IP network); (d) have the ability to move the 'bot fromlocation to location within a domain, retaining its heuristicallyacquired knowledge as it moves¹; and (e) cause no damage to thelocations it visits, respecting applicable security restrictions at eachlocation.¹The ability to spawn replicates of itself is merely an instance of thiscapability. In a simple move operation, the original dies; in areplication mode, the original persists after spawning the replicate.

Because a 'bot can be, for example, required to discover and retainknowledge of the domain in which it operates, a traversal mechanism can,in exemplary embodiments of the present invention, be implemented as astate machine. Implicit in such a design can be, for example, theability to discover and traverse both linearly and hierarchicallyorganized domains in the most efficient manner possible (unless, in agiven exemplary embodiment, it is desirable for a 'bot's traversal to bea random walk).

In exemplary embodiments according to the present invention a 'bot'spayload can have, for example, the following characteristics. It can (a)be able to discover relevant documents at each location to which thetraversal mechanism delivers it; (b) be able to open and analyze eachdocument discovered without causing any changes to the document(including, in particular, updating of any time-and-date stampsassociated with the document)²; (c) be capable of notifying thetraversal mechanism when all relevant documents have been processed inthe current location; (d) have a mechanism, described below, foridentifying documents that are candidates for further semantic analysis,and for rejecting those that are not; (e) have a method for identifyingto a person or to another computer program, documents that are judged tobe candidates for further semantic analysis; and (f) be capable ofmodulating its demands for resources on the system on which it findsitself executing so as to have minimal impact on such system.²In most operating systems, this could be accomplished, for example, bycopying the file to a scratch location and working with the copy, thendeleting it when done with the analysis.

Identifying Candidate Documents

In exemplary embodiments according to the present invention, once atraversal mechanism has delivered a 'bot to a new location, its payloadcan begin executing, looking for documents that are candidates forfurther processing. So that a 'bot may be most useful over the broadestcorpus of documents, a payload's identification mechanism can have, forexample, the following characteristics: (a) be implemented as a rulesprocessing engine, with no (or very few) processing rules hard-codedinto the payload; and (b) read rules stored in a central rules databasewhich will allow centralized management of the rule base shared amongall instances of the 'bot.

The operation of an exemplary payload is illustrated in FIG. 9. Withreference to FIG. 9, the exemplary operation is as follows. When anexemplary 'bot arrives at a suitable location, its payload can bestarted at 900, for example, by the 'bot's traversal mechanism, whichcan then, for example, suspend execution until awoken by a signal formthe payload at the end of the payload's processing (at 990 withreference to FIG. 9).

At 910 a payload can, for example, read a series of document analysisrules from a central rule base 911, storing such rules in internalstorage in such a manner that they can be repeatedly cycled through foreach document being processed. Then, at 920 the payload can, forexample, accesses, for example, a file system 921 or other directorystructure to obtain a list of the documents available at the currentlocation. It is noted that at this point, in exemplary embodiments ofthe present invention, some filtering can occur so that a given 'bot canselect only .doc or .txt files, for example, excluding all others. Thisbehaviour can be controlled, for example, either by hard-coded rules, oras a result of a rules engine using a class of rules applicable to fileselection.

At 930 the exemplary payload can then enter an outer processing loop,which can loop, for example, once per discovered document. If at the endof such outer loop 975 there are no more documents to be processed,i.e., there is a “No” at 975, the payload's processing is completed at990. If there are additional documents at 975, the processing flow can,for example, re-enter the outer loop at 930. For each document found, apayload can, for example, enter an inner loop at 950, which can, forexample, loop once for each rule previously read and stored (at 910). Ifat 970 there are no more unexecuted rules, the processing can, forexample, exit the inner loop and proceed to a score processing operation980 for that document.

A rule processing engine can, for example, apply a current rule to agiven document (or, in exemplary embodiments, to a copy of the document,as described above) and can calculate a weighted score for the rule. Thescores are stored in internal storage for subsequent use during thescoring process. In exemplary embodiments of the present invention,certain rules can be classified, for example, as pass/fail, implyingthat if the rule fails, processing of the document should immediatelycease and a non-suitability flag can be asserted. Some uses of this typeof rule are described below.

When there are no more rules to process (or a non-suitability flag hasbeen asserted), a payload can exit the inner loop at 970 and enter, forexample, a score processing process at 980. Here weighted scorespreviously calculated for the document are aggregated and/or otherwiseprocessed in such a manner that a suitability modulus, for example, canbe calculated for the document. Such a suitability modulus can be ameasure of whatever semantic criteria are desired in a givenapplication, such as, for example, semantic closeness to a given set ofdocuments, semantic distance from a set of patent claims, semanticsimilarity to a certain ideology, etc. If, as described above, inexemplary embodiments of the present invention a non-suitability flaghas been asserted, a zero suitability modulus can be assigned in scoreprocessing 980.

After score processing, one of two actions can take place. For example,the identifiers of all documents that have been processed, along withtheir suitability modula, can be written to or otherwise stored in acentral candidate database 981. Alternatively, only those documentswhose suitability modulus is above a certain threshold value can bestored in such central candidate database 981. Where the first exemplaryoption is chosen, a selection operator can be used to select documentsfor further analysis from central candidate database 981.

At the conclusion of all payload processing, in exemplary embodiments ofthe present invention, a payload can signal the traversal mechanism andthen terminate.

Exemplary Rules

There are a variety of types of rules that can be applied to documentsin exemplary embodiments of the present invention to assess theirsuitability for further semantic processing. Some rules can, forexample, execute completely on their own, with no reliance upon externalinformation. Other rules can draw upon external data sources. Both typesof rules are illustrated in Table II below, which displays a number ofexemplary rules that a 'bot payload can execute, as described above(corresponding to the inner loop 950, 960 and 970, with reference toFIG. 9) with explanations as to their functionalities. TABLE IIEXEMPLARY ′BOT EXECUTABLE RULES External data # Rule required Comments 1If filesize less than None Assume smaller files 50 KB then assert not ofinterest non-suitability flag 2 If filetype not in None Assume otherfile |.doc .txt| then types not of interest assert non-suit- abilityflag 3 If count(<phrase>) > 0 Database of Phrases assumed to be zerothen rule_score = phrases with one or more words long; count * ruleweight weights implement as a loop, one iteration per phrase 4 Ifcount(figures) > 0 None Number of figures may then rule_score = besignificant for count * rule weight desired documents 5 If document isNone Structured documents may structured then be of more interest thanscore = rule unstructured documents weight

Detailed Example Searching for Prior Art to Assert Against IssuedPatents

To illustrate the methods of the present invention, an exemplaryembodiment will next be described using actual textual documents. Inthis example the object of the documentary analysis is to find prior artto invalidate a set of existing patents. Thus there are two inputdocument types: a set of issued patents and a variety of potentiallyanticipating prior art references. As is known, a patentable inventionmust be novel. If one can adduce prior art references that teach theclaimed invention of a patent or set of patents, one can potentiallyinvalidate the patents. Thus, in licensing contexts as well as indefending claims of patent infringement, it is often necessary to knowif an asserted patent can be invalidated. This is done by locating priorart which teaches the claimed invention. The detailed example nextdescribed uses an exemplary embodiment of the present invention toautomate the process of finding prior art.

In exemplary embodiments of the present invention directed to such anapplication, an initial screening search can be done for potentiallyuseful prior art, and then an exemplary system can implement thecomparative analysis. The initial search can be accomplished in variousways. For example, a human researcher can locate a corpus of documentsthat could potentially contain anticipating prior art and deposit themin electronically processable form, in a given directory or database.Alternatively, as described above, a 'bot program can be used toinitially locate a corpus of documents.

Thus the appendices hereto contain two types of input documents. Twoissued patents appearing in Appendix I, and five references which couldpotentially be prior art to these patents. The five potential referencesare divided into three groups. A first group consists of the Marc patentwhich is known to be prior art against the issued patents, as describedbelow. The Marc patent is provided in Appendix II. The second groupconsists of the Maurer patent, a reference cited in each of the twoissued patents, provided in Appendix III. Finally, a third group of twocontrol patents are provided in Appendix IV. The control patents are notsemantically related to the issued patents, and are used for comparisonof results. Finally, Appendix V contains raw data from a semanticanalysis of each of the six references used in the detailed example. Theprocess of obtaining the raw data and its use is described below.

The detailed example was inspired by a recent opinion of the UnitedStates Court of Appeals for the Federal Circuit, Ohio Cellular ProductsCorp. v. Adams U.S.A. Inc., decided on Dec. 23, 1996, available at 41U.S.P.Q.2d 1538 (1996). The subject of the opinion were two related U.S.patents, U.S. Pat. Nos. 4,980,110 and 5,273,702 (the “Issued Patents”),which are directed to methods of forming cross-linked foamed polyolefinarticles. In Ohio Cellular the court held that the two issued patentswere invalid, having been anticipated by U.S. Patent No. 4,524,037 toMarc (“Marc”) directed to a method of forming a flexible thermoplasticresin foam article. Additionally, each of the Issued Patents cites as areference U.S. Pat. No. 4,595,551 to Maurer (“Maurer”) which deals withthe formation of styrenic foam laminates. Assumably there is a closesemantic relationship between the Issued Patents and Maurer. As anillustration of an exemplary embodiment of the present invention, thesemantic distance between the anticipating Marc reference and each ofthe Issued Patents and the Maurer patent was measured. As a control, twopatents completely unrelated to the rest, U.S. Pat. Nos. 4,627,177 and4,364,189 (the “Control Patents”), directed to an insole structure and arunning shoe, were also analyzed and the semantic distance between themand Marc measured as well. Each of the patents used in the example, aswell as the raw data generated by an exemplary semantic analysisthereof, is presented in the appendices which follow. What is nextdescribed are the details of how semantic vectors were formed andcompared in this detailed example, culminating in the results displayedin Table III.

Raw Data

As indicated above, Appendix V contains raw data from the analysis ofthe patents used in this example. The data in Appendix V were generatedusing an exemplary computer program designed to (i) identify key termswhich indicate a semantic content, and (ii) calculate the frequency andassign a weight to each such term, as described above in connection withsemantic vector creation. Instead of terms in isolation, the programlooks at main concepts and subordinate concepts appearing in proximity,calculates the frequency of and assigns a weight to each mainconcept-subordinate concept combination. The program also provides anoverall or composite weight for each main term. For purposes of thedetailed example, a weight based metric was used, so frequency data wasnot needed. However, the exemplary metric made use of synonyms to theconcepts. Thus, for example, with reference to Appendix V(A)(1), if onedocument contained the concept “plastic” and another did not, but didcontain the synonymous words “polyolefin”, “styrenic” or “resilientmaterial”, a semantic comparison could be made by treating thesesynonymous terms as semantically equivalent.

Thus, with reference to Appendix V, for each analyzed document, thereare two alternate listings of the linguistic data presented, appearingin Sections 1 and 2, respectively. The first listing represents the dataused in the exemplary semantic analysis summarized in Tables III, IV andV below. This data is in the format {concept-weight-synonyms}. Thesecond is in the format {concept-frequency-weight} and{concept-frequency-weight-subordinate concept}. All three formats areexamples of semantic vectors that could be generated from the documentsin exemplary embodiments of the present invention.

The {concept-weight-synonyms} data is derived from the{concept-frequency-weight} data by deleting the frequency informationand expansion using a synonyms table, as described above with referenceto FIG. 8. The {concept-frequency-weight} data presents a compositefrequency³ and weight score for each key term derived from the moredetailed {concept-frequency-weight-subordinate concept} data appearingimmediately after it in Section 2 of each part of Appendix V. Althoughonly the data listed in Section 1 of each part of Appendix V was used inthe exemplary semantic distance calculations summarized in Tables IIIand V, the remaining data is provided for completeness, to illustratevarious possibilities in generating semantic vectors.³It is noted that because the frequency values in the{concept-frequency-weight} listings appearing at the beginning of eachSection 2 in Appendix V are composite values, they are not necessarilythe simple sum of all of the instances of a given concept listed in thedetailed {concept-frequency-weight-subordinate concept} data listings.The composite frequency values used in this example data adjust foroverlap.

Table III presents a comparison of the semantic distances between theMarc patent and each of the other patents included in the example usingthe {concept-weight-synonyms} data provided in Section 1 of each part ofAppendix V. Table IV provides the legend for interpreting Table III.TABLE III SEMANTIC DISTANCES FROM MARC Prior Art - U.S. Pat. No.4,524,037 (Marc) Type Patent # Concept w-Delta n w_Avg w (prior art) w(document) Issued 1 4,980,110 Cavity 52 68 42 94 Heating 26 82 95 69Means 65 38 70 5 Plastic (S) 65 48 15 80 Temperature 0 77 77 77 Forming(S) 68 48 14 82 6 Distance 1.92 Issued 2 5,273,702 Cavity 52 68 42 94Forming (S) 75 52 14 89 Heating 35 78 95 60 Means (S) 25 83 70 95Plastic (S) 63 47 15 78 Temperature 5 75 77 72 6 Distance 1.91 Reference4,595,551 Means (S) 20 80 70 90 Plastic (S) 71 51 15 86 Temperature 8 7377 69 3 Distance 4.97 Control 1 4,627,177 Material 11 93 87 98 1Distance 1491.74 Control 2 4,364,189 Means 21 60 70 49 Plastic (S) 71 5115 86 2 Distance 19.43

TABLE IV LEGEND FOR TABLE III Concept A linguistic term that defines asemantic content. w-Delta Difference in Weights. w-Avg Average ofWeights. w(prior art) Weight of the concept in the prior art documentw(document) Weight of the concept in the current document n Number ofmatching concepts. Distance Semantic distance between two documentsgiven by: Sqrt(sum((w-Delta){circumflex over ( )}2 *w-Avg))/(Log(n){circumflex over ( )}3 * 1000). (S) Indicates expansionof concept to include its synonyms.Note:An epsilon value of e = 0.1 was used to prevent division by zero inControl 1.

As can be seen with reference to Tables III and IV, the exemplarysemantic distance metric takes as inputs the number of matchingconcepts, n, the difference in the weights for each such concept betweenthe two documents being compared, w-Delta, and the average of theweights of each such concept over the two documents being compared,w-Avg. The quantities w-Delta and w-Avg are functions of the weight ofeach common concept in the Marc patent (labelled as “w (prior art)” inTable III) and in the document being compared with Marc (labelled as “w(document)” in Table III).

Table III thus corroborates the findings of the Ohio Cellular court,inasmuch as the Marc reference is seen to be of approximately equalsemantic distance to each of the Issued Patents, and that semanticdistance is significantly closer than is the semantic distance betweenMarc and Maurer, or Marc and either of the control patents. Theseresults indicate that using an exemplary embodiment of the presentinvention one can quantify the semantic content of each of a number ofdocuments and can use a quantification of such semantic content, i.e., asemantic vector, to compare the semantic content between any twodocuments using a semantic distance metric.

As can be seen in Table IV, semantic distances in the depicted exemplaryembodiment were calculated using the metric:Semantic distance=Sqrt(sum((w−Delta)A2*w−Avg))/(Log(n)A3*1000)  (Eq. 1).

For purposes of comparison, Table V below depicts the results ofperforming the same analysis as is illustrated in Table III to thesemantic distance between the cited Maurer reference and the two IssuedPatents. As can be seen with reference to Table V, using the exemplaryanalysis and metric described above, the semantic distance between eachof the Issued Patents and Maurer is 1.46 and 1.73, respectively. This ison the same order of magnitude as the semantic distance between the twoissued patents and Marc. It is noted that while Maurer is slightlysemantically closer to the Issued Patents than is Marc, from the pointof view of patent jurisprudence Marc was an invalidating referencewhereas Maurer was not. Thus a human reviewer would generally be neededto analyze the short list of semantically close references to determinewhich are arguably anticipating and which are simply semantically closeto a given patent. Semantic closeness of a reference is a necessary, butnot always sufficient, condition for anticipation of a patent, inasmuchas patents tend to describe aspects of a given invention that are bothold and new in the same document. Additionally, in exemplary embodimentsof the present invention directed to finding prior art to invalidatepatents, a more complex metric such as a “anticipation modulus” could bearticulated, which could take into account factors besides semanticdistance alone, to better model patent anticipation. TABLE V SEMANTICDISTANCES FROM MAURER Cited Reference - U.S. Pat. No. 4,595,551 (Maurer)Concept w-Delta n w_Avg w (reference] w (document) Issued 1 4,980,110Outer 27 80 66 93 Heating 63 38 6 69 Method 10 85 90 80 Styrenic (S) 683 86 80 Temperature 8 73 69 77 Thermoforming (S) 75 45 7 82 6 Distance1.46 Issued 2 5,273,702 Outer 28 80 66 94 Thermoforming (S) 82 48 7 89Heating 54 33 6 60 Method 9 86 90 81 Styrenic (S) 8 82 86 78 Temperature65 40 7 72 6 Distance 1.73Other Metrics

A variety of alternate exemplary semantic comparison metrics could beused in given exemplary embodiments, ranging from the simple to thehighly complex, as may be desirable. For example, a given metric couldoperate on {main term-weight-subordinate term} data such as is providedin Appendix V, or on various other possible data formats. Alternatively,a semantic comparison or distance metric could include inputs for bothweight and frequency values for each common main term between twodocuments being compared. With an increase in the complexity of asemantic distance algorithm there is generally an increase in accuracyor resolution at the cost of increased computing overhead and processingoperations.

For example, using frequency information instead of weight informationan exemplary formula for calculating a semantic distance can be, forexample, a Euclidean distance obtained by taking the square root of thesum of each of a number of f-Delta's squared and dividing that number bythe square of the number n of key terms involved, and then multiplyingsuch a ratio by 100, as expressed in Equation 2 below. In analogousfashion to the w-Delta values of the example of Table III, an f-Deltacan be, for example, the difference in frequency between two commonconcepts. In general terms, such an exemplary formula can be:$\begin{matrix}{\frac{{Sqrt}\left( {{f\quad 1^{2}} + {f\quad 2^{2}} + {f\quad 3^{2}} + {f\quad 4^{2}} + \quad{{+ {f\left( {N - 1} \right)}^{2}}f\quad N^{2}}} \right)}{n^{2}}*100} & \left( {{Eq}.\quad 2} \right)\end{matrix}$where n=the number of common concept terms between the two documentsbeing compared, and fN=the f-Delta between two common concept terms.

As can be seen from Equation 2, in this exemplary metric the semanticdistance can take as inputs, for example, only the composite frequencyvalues of main terms (in more complex embodiments it may be desirable touse f-Deltas based on the detailed {main term-subordinate term} pairsfound in Section 2 of each part of Appendix V, and n would then be thenumber of such common pairs). Thus, referring to Table III, for eachcommon concept between the Marc reference and each of the other patents,the overall frequency values of common concepts (as expanded bysynonyms) could be compared. For example, taking the Marc referenceversus Issued 1, the term “cavity” appears in each of these documents,with frequencies 10 and 13 respectively, as can be seen from AppendixV(A)(2), row 2, and Appendix V(B)(2), row 2. Such an (f-Delta)² can, forexample, be computed as follows: (f-Delta)²=(10−13)²=(−3)²=9.

Obviously, if there are no terms in common between two documents underanalysis, there would be no possible calculation of a semantic distance.Accordingly, Equation 2 reduces to infinity where n=0, denoting infinitesemantic distance. Additionally, if a common concept term has anidentical frequency in each document, the f-Delta for that concept iszero, and there is no contribution to the semantic distance from thatcommon concept, as expected. If all common terms have the same frequencythen the numerator in Equation 2 reduces to zero, denoting no semanticdistance at all.

Various other metrics can be articulated as may be appropriate as afunction of the domain or subject matter to which documents undercomparison relate, or as may define a certain quality, such as, forexample, a “modulus of anticipation” in the patent domain, as notedabove. Such metrics can vary significantly, being functions of the nearinfinite variety of documents that can be compared in exemplaryembodiments of the present invention.

Appendices

The following pages contain the Appendices referred to in the abovediscussion of the detailed example.

APPENDICES

I. Two Issued Patents:

A. Issued Patent No. 1—U.S. Pat. No. 4,980,110

B. Issued Patent No. 2—U.S. Pat. No. 5,273,702

II. Prior Art Reference —U.S. Pat. No. 4,524,037 (Marc)

III. Cited Reference (cited in each Issued Patent)—U.S. Pat. No.4,595,551 (Maurer)

IV. Two Control Patents

A. U.S. Pat. No. 4,627,177

B. U.S. Pat. No. 4,364,189

V. Raw Frequency/Weight Data

A. Appendix IA—U.S. Pat. No. 4,980,110 (Prior Art)

B. Appendix IB—U.S. Pat. No. 5,273,702 (Prior Art)

C. Appendix II—U.S. Pat. No. 4,524,037 (Issued Patent)

D. Appendix III—U.S. Pat. No. 4,595,551 (Cited Reference in Prior Art)

E. Appendix IVA—U.S. Pat. No. 4,627,177 (Control)

F. Appendix IVB—U.S. Pat. No. 4,364,189 (Control)

APPENDIX I Two Issued Patents A. Issued Patent No. 1—U.S. Pat. No.4,980,110 B. Issued Patent No. 2—U.S. Pat. No. 5,273,702 APPENDIX I A.Issued Patent No. 1.—U.S. Pat. No. 4,980,110

U.S. Pat. No. 4,980,110

Nelson, et al. Dec. 25, 1990

Method of forming a cross linked foamed polyolefin composite article

Abstract

A method for forming soft, resilient, smooth, energy dissipatingarticles from foamed partially cross-linked polyolefins wherein sheetstock is cut into a preform and the preform while at room temperature ispositioned within a mold cavity formed by partible mold halves. Thepreforms and the cavity of the molds are so arranged and constructedthat after molding there is no flashing needing trimming because thepolyolefin is substantially confined within the cavity without anylateral projection into the parting surfaces of the mold.

Inventors: Nelson; Donald E. (Adrian, Mich.); Lammy, Sr.; James E.(Napoleon, Ohio)

Assignee: Ohio Cellular Products, Inc. (Wauseon, Ohio)

Appl. No.: 180824

Filed: Apr. 12, 1988

Current U.S. Class: 264/152; 264/160; 264/241; 264/247; 264/273; 264/321

Intern'l Class: B29C 043/18; B29C 043/20

Field of Search: 264/321,276,279.1,152,160,241,247,273

References Cited [Referenced By] U.S. Patent Documents

1978985 October, 1934 Coff 264/276. 3954537 May, 1976 Alther et al.156/82.  4193957 March, 1980 Kauffman et al. 264/321. 4307471 December,1981 Lovell  2/411. 4315050 February, 1982 Rourke 428/116. 4326303April, 1982 Rappleyea  2/411. 4327049 April, 1982 Miller 264/321.4575470 March, 1986 Fakirov et al. 428/105. 4595551 June, 1986 Maurer264/321. 4676041 June, 1987 Ford 264/279.

Other References

Cross-Linked Polyolefin Foams, Journal of Cellular Plastics, William M.Allen, Jan.-Feb. 1984. Trocellen Cross-Linked Polyethylene Foam the NewFashion in foams for the 1980's—Dynamit Nobel of America Inc.

Primary Examiner: Lowe; James

Attorney, Agent or Firm: Neuman, Williams, Anderson & Olson

Claims

What is claimed is:

1. A method for forming a soft, resilient, self-supporting,energy-dissipating article in a mold having partible mold portions, saidmold, when in a closed position, defining an article forming cavitywhich includes a smooth arcuate edge and said mold having a peripheralparting surface, said method comprising: cutting sheet stock of foamed,cross-linked polyolefin into preforms having a rough edge, saidpolyolefin being at least capable of being sufficiently thermoformed toallow a rough edge to be formed into a smooth edge, and said preforms,in plan view, having a peripheral configuration substantiallycorresponding to the peripheral shape of the cavity in plan peripheralview; at about room temperature, positioning a sufficient number of saidpreforms and, optionally at least one insert, into a mold portion sothat upon closing and heating the mold said preform, or preforms, andoptional insert are placed in compressive contact with the cavity andare substantially confined within said cavity without laterallyprojecting into said peripheral parting surface; heating a closed moldcontaining said preforms and optional insert for a sufficient period oftime to allow said rough edge of said polyolefin to be formed into asmooth edge by contact with said smooth edge of said mold cavity andwherein, when plural preforms are used, and/or said optional insert isemployed, said heating is done at a sufficient temperature for asufficient time to form a bonded unitary article.

2. The method of claim 1, wherein a single preform is so positioned insaid mold portion.

3. The method of claim 1 wherein at least two such preforms are sopositioned.

4. The method of claim 1 wherein at least one insert is positioned in amold portion.

5. The method of claim 1 wherein said insert carries integral fasteningmeans.

6. The method of claim 4 wherein said insert is a nonfoamed rigidorganic polymer.

7. The method of claim 4 wherein said insert is a foamed, cross-linkedpolyolefin having a greater density than the density of said preform.

8. The method of claim 7 wherein said preform has a density of about 2to about 8 #/Ft.sup.3 and said insert has a density in excess of about 4#/Ft.sup.3.

9. The method of claim 1 wherein said polyolefin is a closed cellpolyethylene.

10. The method of claim 5 wherein said preform and said insert aregenerally C-shaped.

11. The method of claim 1 wherein said heating is also done for asufficient period of time that the outwardly exposed surface of saidpreform becomes smoother. 12. A method for forming a solidself-supporting resilient cross-linked, foamed moldable polyolefin intoa soft, energy-dissipating article in a mold having partible moldportions, said mold, when in a closed position defining an articleforming cavity and having a peripheral parting surface, the methodcomprising: cutting stock of said polyolefin into preforms; at aboutroom temperature positioning a sufficient number of said preforms, and,optionally, at least one insert, into said mold so that upon closingsaid mold and heating same, said mold cavity is filled with saidsufficient number of preforms, and optional insert, but without eitherlaterally extending into said peripheral parting surface; closing saidmold and heating said closed mold containing said preforms, and optionalinsert, for a sufficient period of time for said preforms to conform tothe adjacent mold cavity and said optional insert, when present, .+−.obond to an adjacent portion of at least one of said sufficient number ofpreforms and thereby form a bonded, single piece article, said methodthereby producing an article which is substantially free of flashing.

13. The method of claim 12 wherein said sufficient number of preforms isone.

14. The method of claim 12 wherein said sufficient number of preforms,and said optional insert fill said mold cavity at about room temperaturewhen said mold is closed and prior to said heating.

15. The method of claim 13 wherein an insert is positioned in said moldso as to be enveloped by at least two contacting preforms.

16. The method of claim 12 wherein at least one insert is employed, saidinsert having means thereon for fastening said insert and single piecearticle to a member carrying complementary means for interengageablyfastening to said insert fastening means.

17. The method of claim 16 wherein said insert's fastening meanscomprises an orifice.

18. The method of claim 12 wherein neither said optional insert or anyof said sufficient number of preforms is formed of a polyurethane or apolyurethane forming precursor.

19. The method of claim 12 wherein (i) at least one of said number ofpreforms and/or said insert are provided with perforate indicia andwherein said perforate indicia carrying preform and/or insert are sopositioned in said mold that upon closing said mold and heating, foamedcross-linked polyolefin from a preform, enters into said perforateindicia.

20. The method of claim 19 wherein said foamed cross-linked polyolefinwhich enters said perforate indicia is of a color different than saidpreform and/or insert provided with said perforate indicia.

21. A method for molding a foamed cross-linked polyolefin in a moldhaving partible mold portions comprising positioning said foamedcross-linked polyolefin while substantially at about room temperature ina cavity portion of said mold, closing said partible mold portions andheating said mold and said polyolefin so as to mold and conform outerportions of said polyolefin to the surface of the mold cavity, theamount of polyolefin being such that during said heating substantiallyno polyolefin extends into the mating parting surfaces of the closedpartible mold portions.

22. The method for forming a molded foamed cross-linked polyolefinarticle which is substantially free of flashing in a mold havingpartible mold halves which when closed define a cavity and a contiguousperipheral mold parting line comprising: positioning, while atsubstantially room temperature, foamed cross-linked polyolefin into acavity portion of said mold; closing said mold; heating said mold for asufficient period of time to form said article.

23. The method of claim 22 wherein the amount of polyolefin materialpositioned in the mold is insufficient to substantially extend into saidparting line upon closing said mold and heating.

DESCRIPTION TECHNICAL FIELD

The present invention relates to the manufacture of cushioning, orenergy absorbing, materials such as, for example, that traditionallyused in athletic equipment. Even more particularly the present inventionrelates to methods of molding a moldable, cross-linked, foamedpolyolefin. The present invention is also directed to methods forproducing tenaciously bonded laminates of cross-linked closed-cellfoamed polyolefin in which one of the laminate layers has a densitydifferent than the other laminate layer.

BACKGROUND ART

Articles have been manufactured in the past from foamed, cross-linkedpolyolefin wherein such articles were intended for use as shockabsorbing, or cushioning members, in a wide variety of applications,including athletic equipment. Such members have been manufactured byothers by a process wherein a panel, or sheet-stock, of foamedcross-linked polyolefin (FXLPO), particularly polyethylene, is heated toan elevated temperature and this preheated material then manuallypositioned within a mold in such manner that a peripheral portion isclamped and sealed in the parting line of complimentary partible moldelements. The material can be further heated and either vacuum molded orcompression molded to a preselected shape. It will be appreciated thatdifficulty is encountered in handling such heated sheet stock because ofthe tacky, adhesive and cohesive nature of the heated FXLPO material.Quite commonly in manually handling the heated FXLPO panel, portionsthereof stick together prior to proper positioning in the mold, henceresulting in a situation where an acceptable product can not bemanufactured and material is wasted. Additionally, because of theclamping of the peripheral boundary of the panel in the mold partingline a great deal of waste flashing is created and must be removed.This, of course, uneconomically increases labor costs and materialcosts.

The problems noted above are common in forming various pads for sportsand athletic equipment such as, for example, hip pads, thigh pads, andknee pads for football equipment. The laterally extending flashingproblem in forming such pads is particularly troublesome from a laborand wasted material point of view.

Present hip pad configurations for use with football equipment,generally have substantially raised, somewhat centrally located portionsextending outwardly from a base portion. With the above-describedmanufacturing techniques currently employed, it is expensive to formsuch raised portions of a material which is not the same as the materialof the base portion of the hip pad. That is, because of the difficultyin handling the tacky, hot sheet stock and the problem of accuratelymanually positioning, and indexing, a different material unto such atacky material, such pads are unitarily formed from a single piece ofsheet stock. It would be desirable to have a process wherein such hippads could be formed with the raised portion and base portion being ofdifferent materials.

In manufacturing thigh pads by the above process there currently is aproblem with regard to unacceptable entrapment of air during forming andalso difficulty in properly indexing the components used to form thesepads. Such thigh pads typically would be formed by first positioning aheated panel of cross-linked, foamed polyolefin in a mold portion,followed by positioning a rigid plastic insert upon the preheated panel.This, in turn, would then be followed by positioning another panel ofheated, foamed, cross-linked polyolefin onto the plastic insert in amanner so as to both encapsulate the insert between the two panels, andjoin the panels at their periphery. The materials would then beperipherally clamped at a mold parting line. This technique, because ofthe adhesive nature of the heated panels, obviously creates an airentrapment problem if the air is not removed as the laminate is beingbuilt up. The removal of such air when handling the sticky, heatedpanels is indeed, a difficult task. The entrapped air then creates airpockets during molding, resulting in a product which could beunacceptable. Indexing is also quite difficult when one considers thesticky, adhesive and cohesive characteristics of the FXLPO which isbeing handled. Both of these problems contribute to poor quality,increased labor costs and increased wasted material.

Thus it will be seen that there is a need in the art for providing aprocess wherein products can be formed without encountering theundesired sticking problem which results when handling heated, foamed,cross-linked polyolefin. A process is also needed wherein the undesiredformation of laterally extending flashing during the molding operationis virtually eliminated. A process is also needed wherein laminates canbe formed such as, for example, thigh pads without encountering severeair entrapment problems between the various layers.

DISCLOSURE OF THE INVENTION

In accordance with the present invention an improved process is providedwhich satisfies the above indicated needs in the art.

In accordance with one feature of the present invention a process isprovided for forming a soft resilient self-supporting energy-dissipatingarticle in a mold having partible mold portions, the mold when in aclosed position, defining an article forming cavity which includes asmooth arcuate edge and said mold having a peripheral parting surface,the process comprises: cutting sheet stock of foamed resilientcross-linked polyolefin into preforms inherently having a somewhat roughnon-arcuate edge, said polyolefin being at least capable of beingsufficiently thermoformed, or molded, to allow such edge to be formedinto an arcuate smooth edge, and said preforms, in plan view, having inone embodiment a peripheral configuration, when in a relaxed condition,substantially corresponding to the peripheral shape of the cavity inplan peripheral view; at about room temperature, positioning asufficient number of said preforms and, optionally, at least one insertinto a mold portion so that upon closing and heating the mold saidpreform or preforms and optional insert are placed in gentle compressivecontact with the cavity and are substantially confined within saidcavity without lateral projection into said peripheral parting surface;closing the mold and heating the closed mold for a sufficient period oftime to allow said non-arcuate, rough edge of said polyolefin to bethermoformed (heat formed) into a smooth, arcuate edge by contact withthe smooth arcuate edge of said mold cavity. When plural preforms areused and/or said optional insert is employed, the heating is sufficientto form a bonded unitary article.

In another embodiment, e.g. when the mold cavity is arcuate in planview, the preform can be cut as a generally rectilinear member and themember bent when positioning in the mold as opposed to the previousembodiment where it can be directly positioned in the mold cavitywithout significant bending.

In accordance with another feature of this invention an article ofmanufacture is provided which is a laminate comprised of a first portionof a foamed cross-linked polyolefin and a second portion of a foamedcross-linked polyolefin tenaciously bonded to said first portion, saidsecond portion having a density greater than said first portion. Inaccordance with another feature of this invention, such laminate carriesfastening means and is employed as a cushioning means, e.g. internallyof protective headgear like the jaw pad in a football helmet. Inaccordance with another feature of this invention there is provided amethod for forming a solid self-supporting resilient cross-linked,foamed moldable polyolefin into a soft, energy-dissipating article in amold having partible mold portions, said mold, when in a closed positiondefining an article forming cavity and having a peripheral partingsurface, the method comprising: cutting stock of said polyolefin intopreforms; at about room temperature positioning a sufficient number ofsaid preforms, and, optionally, at least one insert, into said mold sothat upon closing said mold and heating same, said mold cavity is filledwith said sufficient number of preforms, and optional insert, butwithout either, or any, laterally extending into said peripheral partingsurface; closing said mold and heating said closed mold containing saidpreforms, and optional insert, for a sufficient period of time for saidpreforms to conform to the adjacent mold cavity and said optionalinsert, when present, to bond to an adjacent portion of at least one ofsaid sufficient number of preforms and thereby form a bonded, singlepiece article which is substantially free of flashing.

In accordance with another feature of this invention, a laminatedarticle is provided comprising a first layer of foamed cross-linkedpolyolefin and a second layer of material overlaying said first layer ofpolyolefin, said second layer carrying perforate indicia and a portionof said first layer extending into said perforate indicia of said secondlayer. When different colored layers are employed the configuration canprovide attractive identification and aesthetic appeal.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more apparent by reference to thedrawings wherein:

FIG. 1 illustrates the cutting of sheet stock into preforms;

FIG. 2 illustrates a mold, preforms and an insert which are used inaccordance with the method of this invention;

FIG. 3 is a three dimensional representation of one of the productsformed in accordance with the present invention;

FIG. 4 is a three dimensional representation of a protective head gearwhich is provided with the article shown in FIG. 3; 15 FIG. 5 is asectional view taken along the line 5-5 of FIG. 4;

FIG. 6 illustrates the preforms and an insert employed in accordancewith the present invention to form a thigh pad;

FIG. 7 is a three dimensional representation of a mold used to form sucha thigh pad;

FIG. 8 shows the mold of FIG. 7 in a closed position and containing thepreforms and insert of FIG. 6;

FIG. 9 is a three dimensional representation of a thigh pad formed inaccordance with the present invention;

FIG. 10 is a sectional view taken along the line 10-10 of FIG. 8 andshows a thigh pad being molded;

FIG. 11 is a sectional view taken along the line 11-11 of FIG. 8 alsoshowing the molding of a thigh pad.

DETAILED DESCRIPTION OF THE INVENTION

As previously indicated the present invention contemplates the use ofthe foamed cross-linked polyolefin (FXLPO) material in the form of asheet or bun-stock. Such materials are readily commercially availableand are supplied by Dynamit Nobel of America, Inc. under the trademarkTROCELLEN, and by Monarch Rubber Co., under their designation Evalite.The polyolefins can be homopolymers of ethylene or homopolymers ofpropylene and/or copolymers of ethylene and/or propylene withcopolymerizable monoolefinically unsaturated monomers such as, forexample, vinyl acetate. One such copolyxer which is widely commerciallyavailable is a copolymer of ethylene and vinyl acetate, typically withup to about 30% by weight of vinyl acetate as the comonomer. Thesematerials are cross-linked by irradiation or by the use of chemicalcross-linking agents such as the peroxides and hydroperoxides. Foamingis accomplished by using any of many well-known chemical or physicalfoaming agents. The (FXLPO) materials contemplated for use in thepresent invention obviously are not cross-linked to the extent that theyare no longer formable. That is, the materials employed should only bepartially cross-linked and the cross-linking should allow for thematerials to be put into a mold and possess sufficient moldability, ordeformability, when heated so that at least a rough cut edge can conform(flow or deform) to a smooth arcuate surface of the mold, whereby anarticle can be formed which has smooth edges rather than rough cutedges. These materials generally have high heat resistance, good fatigueresistance and good resistance to a wide variety of environmentalconditions. In general the densities of the foamed cross-linkedpolyolefins (FXLPO) employed can vary over a wide range. Quiteoutstanding results will be obtained using materials having densities inthe range of about 2 to about 10 or 12 pounds per cubic foot.

Referring to FIGS. 1-5, sheet stock 26 of the FXLPO material is firstcut, for example using a die cutter 22, to form preforms 28. Molding ofa preform, or a plurality of preforms either with or without the use ofan insert, is effected by the use of metallic partible molds,respectively 10 and 12. Partible mold portion 12 includes an articleforming cavity 18, which as seen in FIG. 2, is generally arcuate, orC-shaped, in plan view. Cavity 18 is so formed that its lower edges 20are smooth and rounded so as to produce a more comfortable andaesthetically appealing product. When in a closed position theperipheral parting surfaces 14 and 16 of the mold are brought intointimate contact with each other. Partible mold portion 10 is providedwith an inwardly (or downwardly) projecting molding surface 21 whichupon closing snugly nests within cavity 18 and defines an articlemolding surface.

At least one preform 28 is employed which, in plan view, has aperipheral configuration substantially corresponding to the peripheralshape of cavity 18 in plan view. That is both cavity 18 and preform 28are substantially the same in plan peripheral view. Alternatively,however, a preform can be cut which is generally a rectilinear preform30 by use of a suitable cutting die 24. When a rectilinear member 30 isemployed, it will need to be bent before it can be positioned withinmold cavity 18. This is in contrast to the use of the C-shaped preform28 which may be substantially directly placed within cavity 18. Ineither case, however, because of the cutting operation, the preforms aregenerally provided with rough cut edges 32. Of course, for aestheticpurposes and comfort when used in contact with the skin, these roughedges need to be formed into smooth rounded edges in the mold.

In referring to FIG. 2 alternate options of the present invention becomeapparent. In FIG. 2 plural preforms are employed, namely a preform 28and a preform 29 which generally is of lesser thickness. These preformsobviously can be tailored for preselected end uses by using FXLPOmaterials which have different densities. When different densities arenot desired, a single preform 28 may be employed.

FIG. 2 also illustrates the optional use of a insert 34 which integrallycarries suitable fastening means 36. Fastening means 36 can be any of anumerous variety of available fasteners, including metallic fastenershaving orifices for snapping engagement with complementary fasteningmeans on another article, or the fastening means can be Velcro material.There may, of course, be no need to employ any insert or an insert whichcarries fastening means depending on the desired end use.

In the embodiment set forth in FIG. 3, a soft, resilient,self-supporting energy dissipating jaw pad 42, which will be employedinside of a protective head gear such as, for example, football helmet38 is illustrated. Such a pad needs to possess optional insert 34 whichcarries appropriate fastening means 36. Generally, insert 34 may be ofany convenient material depending on the ultimate use including plastics(both thermoplastic and thermoset) or metals, for example aluminum, andpaperboard. The insert can also be a reinforcing mat such as a glassfiber reinforcing mat or a polymeric reinforcing mat such as apolyethylene terephthalate fibrous mat. The insert may, or may not,include the integral fastening means 36 depending on the ultimateproduct use. The insert may take the form of a sheet, either curvilinearor planar, a film or a fabric, either woven or nor-woven. Outstandingproducts have been produced in accordance with this invention by usinginserts whose resistance to flexure has been greater than that of theFXLPO material used for the preform(s), i.e. the insert generally willbe less elastic or more rigid. For the jaw pad example, the insert maybe a polyolefin, preferably a cross-linked polyolefin and most desirablya foamed cross-linked polyolefin but one which has slighter greaterdensity then the preform 28, and optional preform 29.

Preform 28 is positioned within cavity 18, and is overlayed withoptional preform 29. Insert 34 is then positioned, or overlayed, on topof preform 29. Partible mold 10 is then brought into contact with thelower partible mold portion 12. The article defining molding surface ofthe formed cavity (including the snugly nesting molding surface 21) andthe preform, or preforms, and optional insert, are selected such thatupon closing the mold, preform 28, or optional preform 29 and theoptional insert 34 are placed in gentle compressive contact with thecavity. Additionally, whether a single preform is used or pluralpreforms, either with or without an insert, the gently compressedmaterial to be molded and/or bonded is within the article definingsurfaces of the mold and are substantially confined within the mold andits cavity forming surface without laterally projecting into theperipheral parting surfaces 14 and 16 of mold halves 10 and 12.

The closed mold containing the molding materials 28, 29, 34 is thenheated in any convenient manner such as, for example, in an air heatedoven. The molds can also be heated by putting them in contact with anysuitable heat transfer medium or for that matter designing the molds toallow the passage of a heat transfer medium therethrough. As previouslyindicated, it is generally desired to convert rough cut edges 32 to asmooth curved arcuate edge 33 by molding the rough cut edge 32 incontact with the smooth edge 20 of the cavity 18. Consequently, the moldand materials to be molded, are heated to a temperature and for a timeat least sufficient to effect that objective, that is for the rough edgeto be molded and formed into a curved smooth edge. Typically, theheating is done at a temperature in the range of about 250.degree. F. toabout 500.degree. F. for about 1 to about 20 minutes. During suchheating not only are rough edges converted to smooth edges but ingeneral the entire preform 28 takes on the configuration of the moldingsurfaces and results in the production of a much smoother aestheticallypleasing article.

After cooling, final article 42 is removed from the mold. This article,which is represented in the form of a C-shaped member, is employedinside of protective headgear like football helmet 38, as a safety andenergy absorbing member. Headgear 38 includes a rigid protective shell40 of a suitable polymeric material and the article 42 is disposedinternally of shell 40 as a jaw pad. The jaw pad 42 is attached to theshell 40 by suitable inter-engaging fastening means, generallydesignated 44, one part 46 of which is carried by the shell 40 and theother part 36 of which is carried by jaw pad 42. The fastening means 44can best be seen in FIG. 5 which shows the attachment of jaw pad 42 toshell 40 by the inter-engaging fastening means 46 and 36, respectively.In the preferred embodiment the fastening means 44 will be conventionalmetallic snap fasteners.

Thus from the above it will be apparent that the present method providesa technique whereby a variety of FXLPO materials, e.g. of varyingdensities, can be tenaciously heat bonded to each other and/or moldedinto finished articles having smooth surfaces. By properly selecting atleast one preform (or a plurality of preforms) either with or without aninsert, to fill the cavity so that the preform, or preforms and optionalinsert are placed in gentle compressive contact with the moldingsurfaces but are confined within the cavity and without laterallyprojecting into the peripheral parting surface, production economies areobtained. There is no flashing which must be removed because thematerials do not significantly enter the peripheral parting surface, orline, of the mold during molding.

Referring now to FIGS. 6-11, another embodiment of the invention isillustrated wherein a thigh pad 48 conventionally used with footballequipment is fabricated. The thigh pad is generally illustrated in FIG.9 and includes a somewhat centrally disposed recessed panel 64 and aslight annular collar 62. The thigh pad in transverse cross section isgenerally concave. Thigh pad 48 is formed from two preforms, best seenin FIG. 6, 50 and 52 respectively with the upper portions 54 of each ofthe preforms being somewhat larger than the lower, or bottom portions,56 and the sides thereof gradually tapering from upper portion 54 tolower portions 56. Preforms 50 and 52 are each formed from a foamedcross-linked polyolefin and the specific materials of each preform maybe the same or different. In addition to the preforms, an insert 58 isemployed with the insert having disposed along its longitudinaldimension a plurality of downwardly protruding ribs 60. In transversecross section, both through the main body portion of insert 58 andthrough ribs 60, the insert is upwardly concave. The preform, 50, whichis disposed upwardly of the upwardly concave insert generally will be ofa slightly smaller area than will the lower preform, 52.

Preforms 50 and 52 are cut from a stock with a cutting die and alsoinclude rough edges 33. Insert 58 is generally formed of a rigidnon-foamed material, preferably an organic polymer (such as, forexample, polyvinyl chloride or the like) or a metal (like aluminum) and,obviously, adds strength and rigidity to the thigh pad. Outstandingresults will be obtained using a rigid polyvinyl chloride insert, e.g. acurvilinear sheet with a thickness of about {fraction (1/16)} to about ⅛inch. Insert 58 becomes substantially totally enveloped and encapsulatedbetween preforms 50 and 52 and preforms 50 and 52 in turn becometenaciously peripherally bonded to each other and, depending on itscomposition, to insert 58 during the molding operation generallyillustrated in FIGS. 7, 8, 10 and 11.

The molds include partible mold halves, 66 and 68, which mold halves arepivotally mounted, as by rod 74, and can be closed and clamped by theclamping mechanism 76. The mold includes peripheral parting surfaces 70and 72, respectively. The preforms and insert are such that preforms 50and 52 are gently compressed within the mold cavity upon closing of themold halves. The preforms are also substantially confined within themolding cavity without lateral projection into the mold partingsurfaces, e.g. 70 and 72. This is best exemplified in FIGS. 10 and 11wherein it will be seen that upon first positioning the lower preform 52into the partible mold 66 and then, overlaying, insert 58 thereon,followed by the positioning of preform 50 thereover, the insert andpreforms are confined within the article defining surfaces of the moldcavity and do not project laterally into the mold parting surfaces. Uponheating, small portions of preforms 50 and 52 may tend to creep into themold parting surfaces, but if this happens the amount is soinsignificant that virtually no unacceptable flashing forms and that thefinal article 48 still does not need to be trimmed. The closed mold withthe insert and preforms are heated at a temperature for a timesufficient such that rough edges, like edges 33, can flow and form intothe smooth arcuate edges 78 by contact with the smooth curved moldingsurfaces.

Because the preform or preforms, and optional inserts, are allpositioned in a mold while the insert and preforms are at roomtemperature, there is little difficulty in positioning them in theproper place because they are not in a heated or sticky state whenhandled. This provides an improvement over the practices notedpreviously. This convenient indexing is itself a great benefit but italso appears that undesired air entrapment is also virtually eliminated.

It will be recalled that hip pad configurations were indicated to have araised centrally located portion but because of the handling of heatedpanels it is expensive and difficult to form raised portions on the hippad by inserting a material which is not the same as the material of thebase portion. The difficulty in handling a tacky heated sheet stockinsert is the cause of the problem. In accordance with the presentinvention, because the FXLPO materials are positioned within the mold atroom temperature, this problem is obviated. The method provides anopportunity to easily form the raised portions of a hip pad from amaterial which is not the same as the base material.

Based on the foregoing, it will be apparent that many options exist fortaking advantage of the present invention. For example, and, althoughnot shown, perhaps best appreciated by reference to the embodimentdescribed with respect to FIG. 2, at least one of the preforms 29 and/orthe insert 34 can be provided with perforate indicia so that uponclosing of the mold, and molding by heating, foamed cross-linkedpolyolefin from a different preform can enter into the perforateindicia. This perforate indicia can take the form of any suitableopening, or openings, which defines lettering and/or a suitable design.The lettering obviously can be used for identification and/oradvertising purposes. The design can similarly be a manufacturer's logoand function similarly. In this way, and especially in the case whendifferent colors are used in the preform and/or insert, the laminatedconfiguration can provide an attractive identification and aestheticallyappealing structure. Thus, for example, if it were desired to form, inaccordance with FIG. 2, an article (other than a jaw pad or one needinginsert 34) having some distinctive indicia thereon, preform 29 wouldhave an opening or openings made through it. The opening(s) would, forexample, be a name so that when molded FXLPO material from preform 28would enter the openings and provide a contrasting indicia on the uppersurface of preform 29. Use of contrasting colors for preforms 29 and 28provides an opportunity for many appealing structures.

In a like manner, insert 34 could be provided with perforate indicia(either with or without fastening means 36) so as to allow theadjacently downwardly FXLPO material from a preform 29 (or 28 dependingon how many are used) to form the identification or design indicia byentering and generally heat bonding to the indicia defining surfaces.

While no vents are shown in the molds, it is generally preferred toprovide appropriately arranged small vent holes. Additionally, inpracticing this invention, it has been found that non-cross linkedfoamed polyolefins are generally not satisfactory for the presentpurposes because they contract and soften and flow when heated.Outstanding shock energy absorbing materials have been produced withmaterials indicated above and without the utilization of anypolyurethane or foamed polyurethane or any precursors to a polyurethaneor foamed polyurethane. Additionally it should be noted that tenaciousteat bonding between FXLPO materials is effected without the necessityfor dipping any of the preforms or inserts into organic peroxidesolutions.

Having described the invention it will of course be apparent thatmodifications are possible which pursuant to the patent statutes andlaws do not depart from the spirit and scope thereof.

Appendix I B. Issued Patent No. 2—U.S. Pat. No. 5,273,702 Appendix I B.Issued Patent No. 2—U.S. Pat. No. 5,273,702

U.S. Pat. No. 5,273,702

Nelson, et al., Dec. 28, 1993

Method of forming a cross linked foamed polyolefin article

Abstract

A method for forming soft, resilient, smooth, energy dissipatingarticles from foamed partially cross-linked polyolefins wherein sheetstock is cut into a preform and the preform while at room temperature ispositioned within a mold cavity formed by partible mold halves. Thepreforms and the cavity of the molds are so arranged and constructedthat after molding there is no flashing needing trimming because thepolyolefin is substantially confined within the cavity without anylateral projection into the parting surfaces of the mold.

Inventors: Nelson; Donald E. (Adrian, Mich.); Lammy, Sr.; James E.(Napoleon, Ohio)

Assignee: Ohio Cellular Products, Inc. (Wauseon, Ohio)

[*] The portion of the term of this patent subsequent to Dec. 25, 2007has been disclaimed.

Appl. No.: 790222

Filed: Nov. 8, 1991

Current U.S. Class: 264/152; 264/153; 264/276; 264/308; 264/321;264/331.17

Intern'l Class: B29C 043/18; B29C 043/20

Field of Search: 264/321,308,331.17,153,138,276,152

References Cited [Referenced By]

U.S. Patent Documents 1978985 October, 1934 Cobb 264/276. 3108852October, 1963 Olsen 264/321. 3344222 September, 1967 Shapiro et al.264/321. 3954537 May, 1976 Alfter et al. 156/306. 4193957 March, 1980Kauffman et al. 264/321. 4307471 December, 1981 Lovell  2/411. 4315050February, 1982 Rourke 264/259. 4326303 April, 1982 Rappleyea  2/411.4327049 April, 1982 Miller 264/257. 4575470 March, 1986 Fakirov et al.156/307. 4595551 June, 1986 Maurer 264/321. 4676041 June, 1987 Ford264/257. 4980110 December, 1990 Nelson et al. 264/321. Foreign PatentDocuments 251254 May, 1963 AU 264/321. 155019 September, 1984 JP264/321.

Other References

“Trocellen Cross-Linked Polyethylene Foam The New Fashion in Foams forthe 1980's.,” Dynamit Nobel of America Inc., S. Holland, Ill.“Crossed-Linked Polyolefin Foams”, Allen, J. of Cellular Plastics,Jan./Feb. 1984, pp. 70-71.

Primary Examiner: Lowe; James

Attorney, Agent or Firm: McAndrews, Held & Malloy, Ltd.

Parent Case Text

This is a continuation of application Ser. No. 07/541,588, filed Jun.21, 1990, now abandoned, which is a divisional of application Ser. No.07/180,824, filed on Apr. 12, 1988, now U.S. Pat. No. 4,980,110.

Claims

What is claimed is:

1. A method for forming a foamed, cross-linked polyolefin into anarticle in a mold having partible mold portions, said mold, when in aclosed position, defining an article forming cavity which includes asmooth arcuate edge and said mold having a peripheral parting surface,said method comprising the steps of: cutting sheet stock of foamed,cross-linked polyolefin into a preform having a rough edge, saidpolyolefin being at least capable of being sufficiently thermoformed toallow a rough edge to be formed into a smooth edge, and said preform, inplan view, having a peripheral configuration substantially correspondingto the peripheral shape of the cavity in plan peripheral view;positioning said preform, below the temperature at which said preform isrendered tacky or sticky, into a mold portion so that, upon closing andheating the mold, said preform is placed in compressive contact with thecavity and is substantially confined within said cavity withoutlaterally projecting into said peripheral parting surface; and heating aclosed mold containing said preform for a sufficient period of time toallow said rough edge of said polyolefin to be formed into a smooth edgeby contact with said smooth edge of said mold cavity.

2. The method of claim 1, further comprising the step of positioning aninsert into a mold portion, wherein said heating step is done at asufficient temperature and for a sufficient time to form a bondedunitary article.

3. The method of claim 1, further comprising the steps of positioningmore than one preform into a mold portion, wherein said heating is doneat a sufficient temperature and for a sufficient time to form a bondedunitary article.

4. The method of claim 3 further comprising the step of positioning aninsert into a mold portion, wherein said heating step is done at asufficient temperature and for a sufficient time to form a bondedunitary article.

5. The method of claim 4, wherein said insert carries integral fasteningmeans.

6. The method of claim 4, wherein said insert is a nonfoamed rigidorganic polymer.

7. The method of claim 4, wherein said insert is a foamed, cross-linkedpolyolefin having a greater density than the density of said preform.

8. The method of claim 7, wherein said preform has a density of about 2to about 8 lb./ft.sup.3 and said insert has a density in excess of about4 lb./ft.sup.3.

9. The method of claim 4, wherein said preform and said insert aregenerally C-shaped.

10. The method of claim 1, wherein said polyolefin is a closed cellpolyethylene.

11. A method for forming a foamed, cross-linked polyolefin into anarticle in a mold having partible mold portions, said mold, when in aclosed position, defining an article forming cavity and having aperipheral parting surface, the method comprising the steps of: cuttingstock of said polyolefin into a preform; positioning said preform, belowthe temperature at which said preform is rendered tacky or sticky, intosaid mold so that, upon closing said mold and heating same, said moldcavity is filled with said preform but said preform does not laterallyextend into said peripheral parting surface; and closing said mold andheating said closed mold containing said preform for a sufficient periodof time for said preform to conform to the adjacent mold cavity.

12. The method of claim 11, further comprising the step of positioningan insert into a mold portion, wherein said heating step is done at asufficient temperature and for a sufficient time to form a bondedunitary article.

13. The method of claim 11, further comprising the step of positioningmore than one preform it no a mold portion wherein said heating is doneat a sufficient temperature for a sufficient time to form a bondedunitary article.

14. The method of claims 13, further comprising the step of positioningan insert into a mold portion, wherein said heating step is done at asufficient temperature and for a sufficient time to form a bondedunitary article.

15. The method of claim 14, wherein said insert carries integralfastening means.

16. The method of claim 14, wherein said insert is a nonfoamed rigidorganic polymer.

17. The method of claim 14, wherein said insert is a foamed,cross-linked polyolefin having a greater density than the density ofsaid preform.

18. The method of claim 17, wherein said preform has a density of about2 to about 8 lb./ft.sup.3 and said insert has a density in excess ofabout 4 lb./ft.sup.3.

19. The method of claim 14, wherein said preform and said insert aregenerally C-shaped.

20. The method of claim 11, wherein said polyolefin is a closed cellpolyethylene.

21. A method for molding a foamed cross-linked polyolefin in a moldhaving partible mold portions comprising the steps of: positioning saidfoamed cross-linked polyolefin, below the temperature at which saidpolyolefin is rendered tacky or sticky, in a cavity portion of saidmold; closing said partible mold portions; and heating said mold andsaid polyolefin so as to mold and conform outer portions of saidpolyolefin to the surface of the mold cavity; the amount of polyolefinbeing such that, during said heating step, substantially no polyolefinextends into the mating parting surfaces of the closed partible moldportions.

22. A method for forming a molded, foamed, cross-linked polyolefinarticle which is substantially free of flashing in a mold havingpartible mold halves which, when closed, define a cavity and acontiguous peripheral mold parting line, said method comprising thesteps of: positioning formed cross-linked polyolefin, below thetemperature at which said polyolefin is rendered tacky or sticky, into acavity portion of said mold; closing said mold; and heating said moldfor a sufficient period of time to form said article.

23. The method of claim 22, wherein the amount of polyolefin materialpositioned in the mold is insufficient to substantially extend into saidparting line upon closing said mold and heating.

Description TECHNICAL FIELD

The present invention relates to the manufacture of cushioning, orenergy absorbing, materials such as, for example, that traditionallyused in athletic equipment. Even more particularly the present inventionrelates to methods of molding a moldable, cross-linked, foamedpolyolefin. The present invention is also directed to methods forproducing tenaciously bonded laminates of cross-linked closed-cellfoamed polyolefin in which one of the laminate layers has a densitydifferent than the other laminate layer.

BACKGROUND ART

Articles have been manufactured in the past from foamed, cross-linkedpolyolefin wherein such articles were intended for use as shockabsorbing, or cushioning members, in a wide variety of applications,including athletic equipment. Such members have been manufactured byothers by a process wherein a panel, or sheet-stock, of foamedcross-linked polyolefin (FXLPO), particularly polyethylene, is heated toan elevated temperature and this preheated material then manuallypositioned within a mold in such manner that a peripheral portion isclamped and sealed in the parting line of complimentary partible moldelements. The material can be further heated and either vacuum molded orcompression molded to a preselected shape. It will be appreciated thatdifficulty is encountered in handling such heated sheet stock because ofthe tacky, adhesive and cohesive nature of the heated FXLPO material.Quite commonly in manually handling the heated FXLPO panel, portionsthereof stick together prior to proper positioning in the mold, henceresulting in a situation where an acceptable product can not bemanufactured and material is wasted. Additionally, because of theclamping of the peripheral boundary of the panel in the mold partingline a great deal of waste flashing is created and must be removed.This, of course, uneconomically increases labor costs and materialcosts.

The problems noted above are common in forming various pads for sportsand athletic equipment such as, for example, hip pads, thigh pads, andknee pads for football equipment. The laterally extending flashingproblem in forming such pads is particularly troublesome from a laborand wasted material point of view.

Present hip pad configurations for use with football equipment,generally have substantially raised, somewhat centrally located portionsextending outwardly from a base portion. With the above-describedmanufacturing techniques currently employed, it is expensive to formsuch raised portions of a material which is not the same as the materialof the base portion of the hip pad. That is, because of the difficultyin handling the tacky, hot sheet stock and the problem of accuratelymanually positioning, and indexing, a different material unto such atacky material, such pads are unitarily formed from a single piece ofsheet stock. It would be desirable to have a process wherein such hippads could be formed with the raised portion and base portion being ofdifferent materials.

In manufacturing thigh pads by the above process there currently is aproblem with regard to unacceptable entrapment of air during forming andalso difficulty in properly indexing the components used to form thesepads. Such thigh pads typically would be formed by first positioning aheated panel of cross-linked, foamed polyolefin in a mold portion,followed by positioning a rigid plastic insert upon the preheated panel.This, in turn, would then be followed by positioning another panel ofheated, foamed, cross-linked polyolefin onto the plastic insert in amanner so as to both encapsulate the insert between the two panels, andjoin the panels at their periphery. The materials would then beperipherally clamped at a mold parting line. This technique, because ofthe adhesive nature of the heated panels, obviously creates an airentrapment problem if the air is not removed as the laminate is beingbuilt up. The removal of such air when handling the sticky, heatedpanels is indeed, a difficult task. The entrapped air then creates airpockets during molding, resulting in a product which could beunacceptable. Indexing is also quite difficult when one considers thesticky, adhesive and cohesive characteristics of the FXLPO which isbeing handled. Both of these problems contribute to poor quality,increased labor costs and increased wasted material.

Thus it will be seen that there is a need in the art for providing aprocess wherein products can be formed without encountering theundesired sticking problem which results when handling heated, foamed,cross-linked polyolefin. A process is also needed wherein the undesiredformation of laterally extending flashing during the molding operationis virtually eliminated. A process is also needed wherein laminates canbe formed such as, for example, thigh pads without encountering severeair entrapment problems between the various layers.

DISCLOSURE OF THE INVENTION

In accordance with the present invention an improved process is providedwhich satisfies the above indicated needs in the art.

In accordance with one feature of the present invention a process isprovided for forming a soft resilient self-supporting energy-dissipatingarticle in a mold having partible mold portions, the mold when in aclosed position, defining an article forming cavity which includessmooth arcuate edge and said mold having a peripheral parting surface,the process comprises: cutting sheet stock of foamed resilientcross-linked polyolefin into preforms inherently having a somewhat roughnon-arcuate edge, said polyolefin being at least capable of beingsufficiently thermoformed, or molded, to allow such edge to be formedinto an arcuate smooth edge, and said preforms, in plan view, having inone embodiment a peripheral configuration, when in a relaxed condition,substantially corresponding to the peripheral shape of the cavity inplan peripheral view; at about room temperature positioning a sufficientnumber of said preforms and, optionally, at least one insert into a moldportion so that upon closing and heating the mold said preform orpreforms and optional insert are placed in gentle compressive contactwith the cavity and are substantially confined within said cavitywithout lateral projection into said peripheral parting surface; closingthe mold and heating the closed mold for a sufficient period of time toallow said non-arcuate, rough edge of said polyolefin to be thermoformed(heat formed) into a smooth, arcuate edge by contact with the smootharcuate edge of said mold cavity. When plural preforms are used and/orsaid optional insert is employed, the heating is sufficient to form abonded unitary article.

In another embodiment, e.g. when the mold cavity is arcuate in planview, the preform can be cut as a generally rectilinear member and themember bent when positioning in the mold as opposed to the previousembodiment where it can be directly positioned in the mold cavitywithout significant bending.

In accordance with another feature of this invention an article ofmanufacture is provided which is a laminate comprised of a first portionof a foamed cross-linked polyolefin and a second portion of a foamedcross-linked polyolefin tenaciously bonded to said first portion, saidsecond portion having a density greater than said first portion. Inaccordance with another feature of this invention, such laminate carriesfastening means and is employed as a cushioning means, e.g. internallyof protective headgear like the jaw pad in a football helmet.

In accordance with another feature of this invention there is provided amethod for forming a solid self-supporting resilient cross-linked,foamed moldable polyolefin into a soft, energy-dissipating article in amold having partible mold portions, said mold, when in a closed positiondefining an article forming cavity and having a peripheral partingsurface, the method comprising: cutting stock of said polyolefin intopreforms; at about room temperature positioning a sufficient number ofsaid preforms, and, optionally, at least one insert, into said mold sothat upon closing said mold and heating same, said mold cavity is filledwith said sufficient number of preforms, and optional insert, butwithout either, or any, laterally extending into said peripheral partingsurface; closing said mold and heating said closed mold containing saidpreforms, and optional insert, for a sufficient period of time for saidpreforms to conform to the adjacent mold cavity and said optionalinsert, when present, to bond to an adjacent portion of at least one ofsaid sufficient number of preforms and thereby form a bonded, singlepiece article which is substantially free of flashing.

In accordance with another feature of this invention, a laminatedarticle is provided comprising a first layer of foamed cross-linkedpolyolefin and a second layer of material overlaying said first layer ofpolyolefin, said second layer carrying perforate indicia and a portionof said first layer extending into said perforate indicia of said secondlayer. When different colored layers are employed the configuration canprovide attractive identification and aesthetic appeal.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more apparent by reference to thedrawings wherein:

FIG. 1 illustrates the cutting of sheet stock into preforms;

FIG. 2 illustrates a mold, preforms and an insert which are used inaccordance with the method of this invention;

FIG. 3 is a three dimensional representation of one of the productsformed in accordance with the present invention;

FIG. 4 is a three dimensional representation of a protective head gearwhich is provided with the article shown in FIG. 3;

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 4;

FIG. 6 illustrates the preforms and an insert employed in accordancewith the present invention to form a thigh pad;

FIG. 7 is a three dimensional representation of a mold used to form sucha thigh pad;

FIG. 8 shows the mold of FIG. 7 in a closed position and containing thepreforms and insert of FIG. 6;

FIG. 9 is a three dimensional representation of a thigh pad formed inaccordance with the present invention;

FIG. 10 is a sectional view taken along the line 10-10 of FIG. 8 andshows a thigh pad being molded;

FIG. 11 is a sectional view taken along the line 11-11 of FIG. 8 alsoshowing the molding of a thigh pad.

DETAILED DESCRIPTION OF THE INVENTION

As previously indicated the present invention contemplates the use ofthe foamed cross-linked polyolefin (FXLPO) material in the form of asheet or bun-stock. Such materials are readily commercially availableand are supplied by Dynamit Nobel of America, Inc. under the trademarkTrocellen, and by Monarch Rubber Co., under their designation Evalite.The polyolefins can be homopolymers of ethylene or homopolymers ofpropylene and/or copolymers of ethylene and/or propylene withcopolymerizable monoolefinically unsaturated monomers such as, forexample, vinyl acetate. One such copolymer which is widely commerciallyavailable is a copolymer of ethylene and vinyl acetate, typically withup to about 30% by weight of vinyl acetate as the comonomer. Thesematerials are cross-linked by irradiation or by the use of chemicalcross-linking agents such as the peroxides and hydroperoxides. Foamingis accomplished by using any of many well-known chemical or physicalfoaming agents. The (FXLPO) materials contemplated for use in thepresent invention obviously are not cross-linked to the extent that theyare no longer formable. That is, the materials employed should only bepartially cross-linked and the cross-linking should allow for thematerials to be put into a mold and possess sufficient moldability, ordeformability, when heated so that at least a rough cut edge can conform(flow or deform) to a smooth arcuate surface of the mold, whereby anarticle can be formed which has smooth edges rather than rough cutedges. These materials generally have high heat resistance, good fatigueresistance and good resistance to a wide variety of environmentalconditions. In general the densities of the foamed cross-linkedpolyolefins (FXLPO) employed can vary over a wide range. Quiteoutstanding results will be obtained using materials having densities inthe range of about 2 to about 10 or 12 pounds per cubic foot.

Referring to FIGS. 1-5, sheet stock 26 of the FXLPO material is firstcut, for example using a die cutter 22, to form preforms 28. Molding ofa preform, or a plurality of preforms either with or without the use ofan insert, is effected by the use of metallic partible molds,respectively 10 and 12. Partible mold portion 12 includes an articleforming cavity 18, which as seen in FIG. 2, is generally arcuate, orC-shaped, in plan view. Cavity 18 is so formed that its lower edges 20are smooth and rounded so as to produce a more comfortable andaesthetically appealing product. When in a closed position theperipheral parting surfaces 14 and 16 of the mold are brought intointimate contact with each other. Partible mold portion 10 is providedwith an inwardly (or downwardly) projecting molding surface 21 whichupon closing snugly nests within cavity 18 and defines an articlemolding surface.

At least one preform 28 is employed which, in plan view, has aperipheral configuration substantially corresponding to the peripheralshape of cavity 18 in plan view. That is both cavity 18 and preform 28are substantially the same in plan peripheral view. Alternatively,however, a preform can be cut which is generally a rectilinear preform30 by use of a suitable cutting die 24. When a rectilinear member 30 isemployed, it will need to be bent before it can be positioned withinmold cavity 18. This is in contrast to the use of the C-shaped preform28 which may be substantially directly placed within cavity 18. Ineither case, however, because of the cutting operation, the preforms aregenerally provided with rough cut edges 32. Of course, for aestheticpurposes and comfort when used in contact with the skin, these roughedges need to be formed into smooth rounded edges in the mold.

In referring to FIG. 2 alternate options of the present invention becomeapparent. In FIG. 2 plural preforms are employed, namely a preform 28and a preform 29 which generally is of lesser thickness. These preformsobviously can be tailored for preselected end uses by using FXLPOmaterials which have different densities. When different densities arenot desired, a single preform 28 may be employed.

FIG. 2 also illustrates the optional use of a insert 34 which integrallycarries suitable fastening means 36. Fastening means 36 can be any of anumerous variety of available fasteners, including metallic fastenershaving orifices for snapping engagement with complementary fasteningmeans on another article, or the fastening means can be Velcro material.There may, of course, be no need to employ any insert or an insert whichcarries fastening means depending on the desired end use.

In the embodiment set forth in FIG. 3, a soft, resilient,self-supporting energy dissipating jaw pad 42, which will be employedinside of a protective head gear such as, for example, football helmet38 is illustrated. Such a pad needs to possess optional insert 34 whichcarries appropriate fastening means 36. Generally, insert 34 may be ofany convenient material depending on the ultimate use including plastics(both thermoplastic and thermoset) or metals, for example aluminum, andpaperboard. The insert can also be a reinforcing mat such as a glassfiber reinforcing mat or a polymeric reinforcing mat such as apolyethylene terephthalate fibrous mat. The insert may, or may not,include the integral fastening means 36 depending on the ultimateproduct use. The insert may take the form of a sheet, either curvilinearor planar, a film or a fabric, either woven or non-woven. Outstandingproducts have been produced in accordance with this invention by usinginserts whose resistance to flexure has been greater than that of theFXLPO material used for the preform(s), i.e. the insert generally willbe less elastic or more rigid. For the jaw pad example, the insert maybe a polyolefin, preferably a cross-linked polyolefin and most desirablya foamed cross-linked polyolefin but one which has slighter greaterdensity than the preform 28, and optional preform 29.

Preform 28 is positioned within cavity 18, and is overlayed withoptional preform 29. Insert 34 is then positioned, or overlayed, on topof preform 29. Partible mold 10 is then brought into contact with thelower partible mold portion 12. The article defining molding surface ofthe formed cavity (including the snugly nesting molding surface 21) andthe preform, or preforms, and optional insert, are selected so that uponclosing the mold, preform 28, or optional preform 29 and the optionalinsert 34 are placed in gentle compressive contact with the cavity.Additionally, whether a single preform is used or plural preforms,either with or without an insert, the gently compressed material to bemolded and/or bonded is within the article defining surfaces of the moldand are substantially confined within the mold and its cavity formingsurface without laterally projecting into the peripheral partingsurfaces 14 and 16 of mold halves 10 and 12.

The closed mold containing the molding materials 28, 29, 34 is thenheated in any convenient manner such as, for example, in an air heatedoven. The molds can also be heated by putting them in contact with anysuitable heat transfer medium or for that matter designing the molds toallow the passage of a heat transfer medium therethrough. As previouslyindicated, it is generally desired to convert rough cut edges 32 to asmooth curved arcuate edge 33 by molding the rough cut edge 32 incontact with the smooth edge 20 of the cavity 18. Consequently, the moldand materials to be molded, are heated to a temperature and for a timeat least sufficient to effect that objective, that is for the rough edgeto be molded and formed into a curved smooth edge. Typically, theheating is done at a temperature in the range of about 250.degree. F. toabout 500.degree. F. for about 1 to about 20 minutes. During suchheating not only are rough edges converted to smooth edges but ingeneral the entire preform 28 takes on the configuration of the moldingsurfaces and results in the production of a much smoother aestheticallypleasing article.

After cooling, final article 42 is removed from the mold. This article,which is represented in the form of a C-shaped member, is employedinside of protective headgear like football helmet 38, as a safety andenergy absorbing member. Headgear 38 includes a rigid protective shell40 of a suitable polymeric material and the article 42 is disposedinternally of shell 40 as a jaw pad. The jaw pad 42 is attached to theshell 40 by suitable inter-engaging fastening means, generallydesignated 44, one part 46 of which is carried by the shell 40 and theother part 36 of which is carried by jaw pad 42. The fastening means 44can best be seen in FIG. 5 which shows the attachment of jaw pad 42 toshell 40 by the inter-engaging fastening means 46 and 36, respectively.In the preferred embodiment the fastening means 44 will be conventionalmetallic snap fasteners.

Thus from the above it will be apparent that the present method providesa technique whereby a variety of FXLPO materials, e.g. of varyingdensities, can be tenaciously heat bonded to each other and/or moldedinto finished articles having smooth surfaces. By properly selecting atleast one preform (or a plurality of preforms) either with or without aninsert, to fill the cavity so that the preform, or preforms and optionalinsert are placed in gentle compressive contact with the moldingsurfaces but are confined within the cavity and without laterallyprojecting into the peripheral parting surface, production economies areobtained. There is no flashing which must be removed because thematerials do not significantly enter the peripheral parting surface, orline, of the mold during molding.

Referring now to FIGS. 6-11, another embodiment of the invention isillustrated wherein a thigh pad 48 conventionally used with footballequipment is fabricated. The thigh pad is generally illustrated in FIG.9 and includes a somewhat centrally disposed recessed panel 64 and aslight annular collar 62. The thigh pad in transverse cross section isgenerally concave. Thigh pad 48 is formed from two preforms, best seenin FIG. 6, 50 and 52 respectively with the upper portions 54 of each ofthe preforms being somewhat larger than the lower, or bottom portions,56 and the sides thereof gradually tapering from upper portion 54 tolower portions 56. Preforms 50 and 52 are each formed from a foamedcross-linked polyolefin and the specific materials of each preform maybe the same or different. In addition to the preforms, an insert 58 isemployed with the insert having disposed along its longitudinaldimension a plurality of downwardly protruding ribs 60. In transversecross section, both through the main body portion of insert 58 andthrough ribs 60, the insert is upwardly concave. The preform, 50, whichis disposed upwardly of the upwardly concave insert generally will be ofa slightly smaller area than will the lower preform, 52.

Preforms 50 and 52 are cut from a stock with a cutting die and alsoinclude rough edges 33. Insert 58 is generally formed of a rigidnon-foamed material, preferably an organic polymer (such as, forexample, polyvinyl chloride or the like) or a metal (like aluminum) and,obviously, adds strength and rigidity to the thigh pad. Outstandingresults will be obtained using a rigid polyvinyl chloride insert, e.g. acurvilinear sheet with a thickness of about {fraction (1/16)} to about{fraction (1/8)} inch. Insert 58 becomes substantially totally envelopedand encapsulated between preforms 50 and 52 and preforms 50 and 52 inturn become tenaciously peripherally bonded to each other and, dependingon its composition, to insert 58 during the molding operation generallyillustrated in FIGS. 7, 8, 10 and 11.

The molds include partible mold halves, 66 and 68, which mold halves arepivotally mounted, as by rod 74, and can be closed and clamped by theclamping mechanism 76. The mold includes peripheral parting surfaces 70and 72, respectively. The preforms and insert are such that preforms 50and 52 are gently compressed within the mold cavity upon closing of themold halves. The preforms are also substantially confined within themolding cavity without lateral projection into the mold partingsurfaces, e.g. 70 and 72. This is best exemplified in FIGS. 10 and 11wherein it will be seen that upon first positioning the lower preform 52into the partible mold 66 and then, overlaying, insert 58 thereon,followed by the positioning of preform 50 thereover, the insert andpreforms are confined within the article defining surfaces of the moldcavity and do not project laterally into the mold parting surfaces. Uponheating, small portions of preforms 50 and 52 may tend to creep into themold parting surfaces, but if this happens the amount is soinsignificant that virtually no unacceptable flashing forms and that thefinal article 48 still does not need to be trimmed. The closed mold withthe insert and preforms are heated at a temperature for a timesufficient such that rough edges, like edges 33, can flow and form intothe smooth arcuate edges 78 by contact with the smooth curved moldingsurfaces.

Because the preform or preforms, and optional inserts, are allpositioned in a mold while the insert and preforms are at roomtemperature there is little difficulty in positioning them in the properplace because they are not in a heated or sticky state when handled.This provides an improvement over the practices noted previously. Thisconvenient indexing is itself a great benefit but it also appears thatundesired air entrapment is also virtually eliminated.

It will be recalled that hip pad configurations were indicated to have araised centrally located portion but because of the handling of heatedpanels it is expensive and difficult to form raised portions on the hippad by inserting a material which is not the same as the material of thebase portion. The difficulty in handling a tacky heated sheet stockinsert is the cause of the problem. In accordance with the presentinvention, because the FXLPO materials are positioned within the mold atroom temperature, this problem is obviated. The method provides anopportunity to easily form the raised portions of a hip pad from amaterial which is not the same as the base material.

Based on the foregoing, it will be apparent that many options exist fortaking advantage of the present invention. For example, and, althoughnot shown, perhaps best appreciated by reference to the embodimentdescribed with respect to FIG. 2, at least one of the preforms 29 and/orthe insert 34 can be provided with perforate indicia so that uponclosing of the mold, and molding by heating, foamed cross-linkedpolyolefin from a different preform can enter into the perforateindicia. This perforate indicia can take the form of any suitableopening, or openings, which defines lettering and/or a suitable design.The lettering obviously can be used for identification and/oradvertising purposes. The design can similarly be a manufacturer's logoand function similarly. In this way, and especially in the case whendifferent colors are used in the preform and/or insert, the laminatedconfiguration can provide an attractive identification and aestheticallyappealing structure. Thus, for example, if it were desired to form, inaccordance with FIG. 2, an article (other than a jaw pad or one needinginsert 34) having some distinctive indicia thereon, preform 29 wouldhave an opening or openings made through it. The opening(s) would, forexample, be a name so that when molded FXLPO material from preform 28would enter the openings and provide a contrasting indicia on the uppersurface of preform 29. Use of contrasting colors for preforms 29 and 28provides an opportunity for many appealing structures.

In a like manner, insert 34 could be provided with perforate indicia(either with or without fastening means 36) so as to allow theadjacently downwardly FXLPO material from a preform 29 (or 28 dependingon how many are used) to form the identification or design indicia byentering and generally heat bonding to the indicia defining surfaces.

While no vents are shown in the molds, it is generally preferred toprovide appropriately arranged small vent holes. Additionally, inpracticing this invention, it has been found that non-cross linkedfoamed polyolefins are generally not satisfactory for the presentpurposes because they contract and soften and flow when heated.Outstanding shock energy absorbing materials have been produced withmaterials indicated above and without the utilization of anypolyurethane or foamed polyurethane or any precursors to a polyurethaneor foamed polyurethane. Additionally it should be noted that tenaciousheat bonding between FXLPO materials is effected without the necessityfor dipping any of the preforms or inserts into organic peroxidesolutions.

Having described the invention it will of course be apparent thatmodifications are possible which pursuant to the patent statutes andlaws do not depart from the spirit and scope thereof.

APPENDIX II Prior Art Reference—U.S. Pat. No. 4,524,037 (Marc) APPENDIXII Prior Art Reference—U.S. Pat. No. 4,524,037 (Marc)

U.S. Pat. No. 4,524,037

Marc Jun. 18, 1985

Method and apparatus for forming a flexible thermoplastic resin foamarticle using an RF field

Abstract

A process and associated apparatus for forming a foam plastic articleusing a mold with a mold cavity and a pair of electrodes across which anRF field may be impressed. The foam material that is to be processed isinserted into the mold and is then compressed. The compression may be atleast on the ratio of 2 to 1 and perhaps as high or higher than 8:1. AnRF heating field is applied while maintaining the foam materialcompressed and after the heat is terminated, the foam material ispermitted to expand to conform to a mold shape as the material cools.This pre-compression step enables substantial reduction in processingtime.

Inventors: Marc; Michel (48 Ridge Hill Farm Rd., Wellesley, Mass. 02181)

Appl. No.: 408159

Filed: Aug. 16, 1982

Current U.S. Class: 264/413; 264/321; 264/491; 425/174.8E; 425/398;425/817R

Intern'l Class: B29D 027/00

Field of Search: 264/26,321 425/817 R,174.8 E,398

References Cited [Referenced By] U.S. Patent Documents

2946713 July, 1960 Dusina, Jr. et al. 264/321. 2966469 December, 1960Smythe et al. 264/26. 3010157 November, 1961 Cizek 264/26. 3082483March, 1963 Bickford 264/321. 3170974 February, 1965 Jacobs 264/321.3242238 March, 1966 Edberg et al. 264/26. 3243485 March, 1966 Griffin264/26. 3244571 April, 1966 Weisman 264/321. 3331899 July, 1967 Immel264/26. 3345439 October, 1967 Everard et al. 264/26. 3400040 September,1968 Osgood 264/321. 3444275 May, 1969 Willett 264/26. 3475522 October,1969 Garibian et al. 264/26. 3640913 February, 1972 Cerra 264/26.

Primary Examiner: Anderson; Philip

Attorney, Agent or Firm: Wolf, Greenfield & Sacks

Claims

What is claimed is:

1. A process of forming a flexible, thermoplastic foam article using amold with a mold cavity, a pair of electrodes across which an RF fieldmay be impressed and compressing means, said process comprising thesteps of:

-   inserting a preform of the foam material into the mold;-   compressing the foam material with the compressing means;-   applying an RF heating field while maintaining the foam material    compressed to heat the foam material to a temperature below the    temperature at which the foam material would become permanently    deformed into its compressed state;-   withdrawing the compressing means; and-   permitting the foam material to expand to conform to and in    substance fill said mold cavity as the material cools to cause the    foam material to permanently deform to assume the general shape and    size of the mold cavity.

2. A process as set forth in claim 1 wherein said foam material iscompressed by a compression ratio of at least 2 to 1.

3. A process as set forth in claim 1 wherein said foam material iscompressed by a compression ratio of about 8 to 1.

4. A process as set forth in claim 1 including providing a plug tocompress the foam.

5. A process as set forth in claim 4 including inserting the foam in apre-formed shape substantially initially matching the shape of the mold.

6. A process as set forth in claim 5 wherein the step of compressing thefoam is carried out by inserting the pre-formed foam into the mold andthen compressing it by inserting the plug over the foam and into themold.

7. A process as set forth in claim 6 wherein the plug compresses thefoam in the ratio of at least 2 to 1.

8. An apparatus for forming a flexible, thermoplastic foam articlecomprising:

-   a mold having a predetermined shape and size mold cavity;-   a pair of electrodes, one on each side of the mold;-   means for compressing a preform of the foam material in the mold    cavity from a condition in which the foam material in substance    fills said mold cavity, to a condition in which the foam material    fills only a fraction of the volume of the mold cavity; and-   means for applying an RF heating field across the pair of electrodes    while maintaining the foam material compressed over a heating period    to heat the foam material to a temperature below the temperature at    which the foam material would become permanently deformed into its    compressed state; and-   means for withdrawing said compressing means to permit said foam    material to expand after termination of the heating period to allow    it to conform to and in substance fill said mold cavity as the    material cools, the foam material being permanently deformed to    assume the general shape and size of the mold cavity.

9. An apparatus for forming a foam plastic article as defined in claim 8wherein said foam material is polyethylene foam.

10. An apparatus for forming a foam plastic article as defined in claim8 wherein said foam material is polypropylene foam.

11. An apparatus for forming a foam plastic article as defined in claim8 wherein said means for compressing includes a plug.

12. An apparatus for forming a foam plastic article as defined in claim11 wherein either or both said mold cavity and plug have an imprintsurface.

13. An apparatus as set forth in claim 11 wherein said plug fits intosaid mold over said foam.

14. An apparatus for forming a foam plastic article as defined in claim8 wherein the foam material is ethylenevinylacetate.

15. An apparatus for forming a foam plastic article as defined in claim8 wherein the foam material is polyvinylchloride.

Description BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates in general to an RF heating process andassociated apparatus. More particularly, the present invention relatesto an RF heating process employed in the making or forming of moldedplastic parts or pieces, particularly items made of plastic foams suchas polyethylene or polypropylene foam.

The present technique for forming foam articles is illustrated in FIG. 1herein in which there is schematically illustrated a mold 10 having acavity for receiving the unprocessed foam block 12. Herein, for the sakeof simplicity, the article being manufactured is simply of cubic form.However, it is understood that both the prior art technique and thetechnique of the present invention may be used in forming varied sizeand shape articles.

Associated with the mold 10 which may be of silicone rubber, are a pairof electrodes 14 and 16. The electrode 14 may be a movable electrodewhile the electrode 16 may be fixed. FIG. 1 schematically illustrates anRF source 18 coupling across the electrodes 12 and 14. FIG. 1illustrates the foam block 12 having been inserted into the mold withthe electrodes then moved to the position shown in FIG. 1. The RF fieldis then applied by source 18 to cause heating of the foam for thepurpose of curing it and forming it into the desired shape. The foam ispreferably free-formed prior to insertion into the mold and has a shapethat already substantially conforms to the shape of the mold. When theelectrodes 14 and 16 are closed so as to ready the apparatus forheating, there may be a slight compression of the foam block 12.However, the prior art technique has never taught any substantialcompression of the foam, particularly the art has not shown compressionof the foam for the purpose of substantially reducing the heating andcuring time thereof.

In the arrangement illustrated in FIG. 1 the typical heating time whichrepresents some portion of the overall manufacturing cycle time, istypically in the order of about five minutes. It is over this fiveminute interval that RF energy is applied for heating. The mold ispreferably constructed so as to have a high dielectric constant so thatas much heat as possible is dissipated in the material that is beingformed with less material being dissipated in the mold itself.

It is an object of the present invention to provide an improved RFheating process and associated apparatus in which the article can beformed over a heating period that is of substantially reduced duration.In accordance with the present invention it has been found that theheating period can be reduced from the afore-mentioned typical fiveminute interval to on the order of 1½ minutes. This is accomplished inaccordance with the present invention by an RF heating process whichcombines RF heating with the use of a pair of electrodes, in combinationwith, substantial compression of the foam material with the foammaterial being maintained compressed during the heating cycle when theRF energy is applied. It has been found that by carrying out thiscompression while applying RF energy, that the heating time can besubstantially reduced. After the heating cycle is over the previouslycompressed foam is permitted to expand as it cools and it then conformsto the desired over all mold shape.

In accordance with the apparatus of the present invention, in order toprovide the aforementioned compression of the foam material, there maybe provided a plug or the like. This plug can also be constructed ofsilicone rubber preferably loaded to have a high dielectric constant.This plug is temporarily used for compression of foam and is maintainedin use during the heating cycle. The plug is then removed to enableexpansion of the foam into its desired final shape.

BRIEF DESCRIPTION OF THE DRAWING

Numerous other objects, features and advantages of the invention shouldnow become apparent upon the reading of the following detaileddescription taken in conjunction with the accompanying drawing, inwhich:

FIG. 1 is a prior art diagram showing the technique for forming foamarticles with RF energy;

FIG. 2 is an exploded view of the RF heating process of the presentinvention showing an initial step of the process wherein the foam is inthe cavity and the plug is about to be inserted;

FIG. 3 is a further schematic cross sectional view showing thecompressing phase of the invention with the plug being used incombination with the upper electrode for compressing the foam materialduring the heating phase;

FIG. 4 shows a cross sectional view of the same mold after the steps ofFIGS. 2 and 3 with the foam material simply being permitted to expand tothe proper mold shape with the plug having been removed.

DETAILED DESCRIPTION

FIG. 1 has been described previously in connection with the discussionof the prior art arrangement of employing RF heating in the constructionof foam articles or items. FIGS. 2-4 are sequential schematic crosssectional views showing the steps in carrying out the process of thepresent invention. In the prior art arrangement the heating period thatis necessary in order to properly form the part is on the order of aboutfive minutes. With the technique of the present invention exemplified inFIGS. 2-4 this heating period is then reduced substantially to on theorder of 1-1.5 minutes. It is understood that the heating period isfollowed by a cooling period in which the electrodes are cooledpreferably by a liquid cooling technique. A production machine typicallyhas a single heating station and may have multiple cooling stations.

In FIGS. 2-4 there is shown an upper electrode 20 and a lower electrode22. The mold is shown in the form of a silicone rubber mold 24. An RFsource 26 connects between the electrodes 20 and 22. In addition to themold 24 there is also provided a plug 28 used in the process of thepresent invention. The plug 28 may also be constructed of a siliconerubber material preferably loaded so as to have a high dielectricconstant.

FIG. 2 shows the mold 24, the electrodes 20 and 22, and the plug 28.Also shown in FIG. 2 is the uncompressed foam material 30 which is madeof a shape that substantially conforms to the shape of the cavity in themold 24. In FIG. 2 the distance a may be on the order of about 1 inch.

Foam material 30 already has been prepared in a conventional mannerknown to those skilled in the art, such as by the use of an additive, orby treating the material, to render foam material 30 suitable for RFheating. Examples of such known methods of preparing foam material 30are shown in the following U.S. Pat. Nos. 3,640,913; 3,243,485;3,242,238; 3,010,157; and 3,331,899.

FIG. 3 shows the next step in the process in which the foam material 30has been compressed to a dimension b on the order of {fraction (1/8)}inch. There is thus an 8 to 1 compression ratio. This ratio ispreferably at least 2 to 1. It is also noted in FIG. 3 that thiscompression is carried out by means of the plug 28 which has moved inthe direction of the arrow 32. The electrode 20 overlies the plug andthe top surface of the mold 24. While the apparatus is in the positionshown in FIG. 3 the RF generator 26 is energized and RF heating isapplied between the electrodes 20 and 22. The majority of this heat isdissipated in the foam material and because of the compression thereofit has been found that the heating cycle can be reduced substantiallywhich greatly enhances the desirability and flexibility of the presentprocess. After the heating cycle has terminated, the plug is removed asindicated in FIG. 4 and the foam material 30 is simply permitted toexpand so as to fill the mold cavity. In the embodiment illustratedherein the top electrode 20 in a sense forms one side of the moldcavity. In other arrangements a further dielectric material could beused in association with the top electrode for forming one side of themold cavity.

Having described one embodiment of the present invention it should nowbe apparent to those skilled in the art that numerous other embodimentsare contemplated as following within the scope of this invention. Forexample there has been illustrated herein particularly in FIGS. 2-4 oneembodiment of an item that is being constructed. Obviously, manydifferent sizes, shapes and configurations of an item can be formed.Also, inner surfaces of the mold cavity may be in the form of an imprintwhich is desired to be made on one or more surfaces of the part beingmolded. Also, there has been described herein the use of plastic foammaterials such as polyethylene or polypropylene foams. Also, other typesof thermal forming plastic foams may be employed. Also, in place of thedie-cut foam material placed in the mold one can also use a liquidplastic such as plastisol with a blowing agent to provide the endproduct foam.

Appendix III Reference Cited in Each Issued Patent-U.S. Pat. No.4,595,551 APPENDIX III U.S. Pat. No. 4,595,551 (Maurer)

U.S. Pat. No. 4,595,551

Maurer Jun. 17, 1986

Thermoforming of styrenic foam laminates

Abstract

Thermoforming of styrenic foam laminates having at least one outer layerof polyurethane foam having an outer facing of decorative fabric. Priorto thermoforming the laminate is heated to at least the thermoformingtemperature of the styrenic foam but to a temperature such that thedecorative fabric is not degraded. The thermoforming process is usefulin making automobile headliners.

Inventors: Maurer; Richard P. (Wilbraham, Mass.)

Assignee: Monsanto Company (St. Louis, Mo.)

Appl. No.: 653658

Filed: Sep. 21, 1984

Current U.S. Class: 264/413; 264/257; 264/322; 428/316.6; 428/319.7

Intern'l Class: B29C 067/22; B29C 051/14; B29C 051/42

Field Search: 264/46.4,46.8,321,322,257,25

References Cited [Referenced By]

U.S. Patent Documents 2878153 March, 1959 Hacklander 264/46. 3303086February, 1967 Demers 161/159. 3355535 November, 1967 Hain et al.264/321. 3531367 September, 1970 Karsten 161/160. 3565746 February, 1971Stevens 161/160. 3654063 April, 1972 Blackburn et al. 161/125. 3787259January, 1974 Kleinfeld et al. 156/78. 3817818 June, 1974 Riding et al.161/89. 3833259 September, 1974 Pershing 297/452. 4065596 December, 1977Groody 428/215. 4147828 April, 1979 Heckel et al. 428/255. 4167824September, 1979 Wolpa  36/44. 4173505 November, 1979 Jacobs 264/46.4388363 June, 1983 Fountain 428/215. 4476183 October, 1984 Holtrop etal. 428/288. 4489126 December, 1984 Holtrop et al. 428/286. 4529641July, 1985 Holtrop et al. 428/286. 4531994 July, 1985 Holtrop et al.156/307. Foreign Patent Documents 2906259 August, 1980 DE 428/319.

Primary Examiner: Anderson; Philip

Attorney, Agent or Firm: Limpus; Lawrence L.

Claims

I claim:

1. A method of thermoforming a laminate of at least one layer ofstyrenic foam, said laminate having an outer layer of polyurethane foamadhered to the at least one layer of styrenic foam, said methodcomprising:

-   (a) heating said laminate to at least the thermoforming temperature    of said styrenic foam, said temperature being at least about    100.degree. C. at the interface of said styrenic foam and said outer    layer of polyurethane foam and less than the temperature at which    said polyurethane foam degrades, and-   (b) thermoforming said laminate.

2. The method of claim 1 wherein said outer layer of polyurethane foamhas an outer facing of decorative fabric and further comprising heatingsaid laminate to a temperature such that said fabric is not degraded.

3. The method of claim 2 wherein each of said styrenic foam layers hason at least one surface a facing comprising a thermoplastic polymerimpregnated fabric.

4. The method of claim 2 wherein the styrenic foam comprisespolystyrene. 5. The method of claim 4 wherein said laminate is heatedsuch that the temperature at the interface of said outer layer ofpolyurethane and said styrenic foam is at least about 100.degree. C.

6. The method of claim 2 wherein said styrenic foam comprisesstyrene-maleic anhydride copolymer.

7. The method of claim 6 wherein said laminate is heated such that thetemperature of the interface of said polyurethane and said styrenic foamis at least about 115.degree. C.

8. The method of claim 6 wherein each of said styrenic foam layers hason at least one surface a facing comprising a layer of dense styrenicpolymer.

9. The method of claim 3 wherein the laminate comprises in succession anouter layer of styrenic foam, an inner layer of polyurethane foam, aninner layer of styrenic foam and an outer layer of polyurethane foam.

10. The method of claim 9 wherein the styrenic foam comprisespolystyrene.

11. The method of claim 10 wherein said decorative fabric comprises anylon fabric.

12. The method of claim 11 wherein said facing on said styrenic foamlayers comprises an acrylic polymer impregnated non-woven fabric.

13. The method of claim 2 wherein the styrenic foam comprisesstyrene-acrylonitrile copolymer.

14. The method of claim 13 wherein said laminate is heated such that thetemperature of the interface of said polyurethane and said styrenic foamis at least about 105.degree. C.

Description

This invention relates to thermoforming of styrenic foam laminateshaving at least one outer layer of urethane foam.

BACKGROUND OF THE INVENTION

Styrenic foam laminates have been used as acoustical and thermalinsulation for a variety of applications, for instance as automobileheadliners. Recent advances in this area have lead to the development ofthermoformable styrenic foam laminates which can be provided in complexshapes. Such laminates are able to retain a desired shape because of theuse of deformation-resistant coatings, for instance apolymer-impregnated fabric facing on at least one surface of thestyrenic foam components. For illustrative laminates see U.S. patentapplications Ser. Nos. 553,594 filed Nov. 17, 1983 and now U.S. Pat.Nos. 4,476,183; 553,462 filed Nov. 17, 1983 and now U.S. Pat. Nos.4,489,126; 647,095, filed Sep. 4, 1984 and now U.S. Pat. No. 4,526,829;647,096 filed Sep. 4, 1984 and now U.S. Pat. Nos. 4,531,994; 647,311filed Sep. 4, 1984 and now U.S. Pat. Nos. 4,557,970; and 648,547 filedSep. 7, 1984 and now U.S. Pat. No. 4,529,641 all of which areincorporated herein by reference.

To thermoform such laminates to useful shapes for acoustical and thermalinsulation applications, the laminates are preheated to thermoformingtemperatures of the styrenic foam components prior to thermoforming.Such preheating is generally effected as rapidly as possible, forinstance by infrared radiation heaters, which may bring the surfacetemperatures of the laminates to temperatures as high as about177.degree. F. or higher. After such laminates are thermoformed intoshapes for acoustical or thermal insulation applications, it is oftendesirable to provide a decorative trim to the exposed surface of theshaped laminate. For instance, when such thermoformed laminates are usedfor automobile headliners, a decorative trim, such as polyurethane foamcovered with a decorative fabric or vinyl facing, is generally utilizedfor an enhanced aesthetic appearance. Because such layer of polyurethanefoam faced with decorative fabric provides thermal insulation whichwould increase the time for preheating the styrenic foam thermoformingtemperatures, decorative layers are applied to the laminate structuresafter thermoforming to the desired shape. Consideration of overcomingthe adverse increase in heating time by applying heat from hottersources, e.g. infrared radiation heaters, have been dismissed asimpractical because the resulting higher surface temperatures would beexpected to degrade the decorative trim e.g. often faced with nylonfabric.

I also believe that attempts have been made to thermoform thermosetting,phenolic resin-impregnated layers of fiberglass batting havingdecorative trim of urethane foam faced with fabric. I understand thatsuch attempts have been unsuccessful because at thermoformingtemperatures the uncured phenolic resin flows through the decorativetrim resulting in stained and hardened trim.

An object of this invention is to provide a method for thermoformingstyrenic foam laminates having an outer layer of decorative trim ofurethane foam faced with a fabric.

A further object of this invention is to provide a method for suchthermoforming which is free from undue delays in heating andthermoforming processes and which did not adversely affect the aestheticappearance of the decorative trim.

These and other objects of this invention will be apparent from thefollowing description and claims.

SUMMARY OF THE INVENTION

This invention provides a method of thermoforming laminates of at leastone layer of styrenic foam wherein the laminate has an outer layer ofurethane foam adhered to the at least one layer of styrenic foam. Themethod comprises heating such laminate to at least the thermoformingtemperature of the styrenic foam followed by thermoforming the laminate.Preferably the outer layer of urethane foam has an outer facing ofdecorative fabric and the heating is such that the temperature at theouter surface of the decorative fabric is below the temperature at whichthe fabric degrades.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional representation of an oven which can be usedto preheat a styrenic foam/polyurethane foam laminate in the method ofapplicant's invention.

FIG. 2 is a cross-sectional representation of apparatus forthermoforming a preheated styrenic foam/polyurethane foam laminate inthe method of applicant's invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention provides a method of thermoforming laminates comprisingat least one layer of styrenic foam having one or two outer layers ofurethane foam with an outer facing of decorative fabric. In some casesthe laminate can comprise one layer of styrenic foam. In other cases thelaminate can comprise multiple layers of styrenic foam and, optionally,with one or more layers of other polymeric foam material or othernon-foam material. The styrenic foam can comprise polystyrene, styrenecopolymers, such as styrene-maleic anhydride copolymer,styrene-acrylonitrile copolymer and the like. A number of usefullaminates are described in U.S. patent application Ser. No. 553,594,filed Nov. 17, 1983 and now U.S. Pat. No. 4,476,183, incorporated hereinby reference. A preferred laminate comprises in succession an outerlayer of polystyrene foam, an inner layer of polyurethane foam, an innerlayer of polystyrene foam and an outer layer of polyurethane foam facedwith a decorative fabric.

The foam layers of the laminate can be of any thickness desired.Generally the foam layers will have a thickness in the range of fromabout 0.15 centimeters to 1.25 centimeters.

To enable the layers of styrenic foam to retain its thermoformed shapeover a range of environmental conditions, e.g. temperatures up to about75.degree. C. and high humidity, it is desirable that at least onesurface of said at least one layer of styrenic foam have adeformation-resistant coating. In some cases such coating can comprise adense layer of thermoplastic polymer, e.g. a styrenic polymer such aspolystyrene, styrene copolymers such as styrene-maleic anhydridecopolymer or styrene-acrylonitrile copolymer, and the like. In othercases such coating can comprise a thermoplastic polymer-impregnatedfabric where the thermoplastic polymer has a high softening temperature,e.g. above about 75.degree. C., as determined by thermomechanicalanalysis described in U.S. patent application Ser. No. 647,096, filedSep. 4, 1984 and now U.S. Pat. No. 4,531,994, incorporated herein byreference. Such polymer may advantageously comprise acrylic polymers.The impregnated fabric can be woven or non-woven. Preferably non-wovensynthetic fabrics of polyester, nylon or polyolefin are preferred.

The decorative fabric of the outer facing of the outer layer of urethanefoam can be woven or non-woven and can comprise a number of materials,e.g. nylon, polyester, polyolefin, cotton and the like or blends ofmaterials. A preferred fabric will have a napped, pile or veloursurface. In some cases it may be desirable to substitute a vinyl sheetfor the decorative fabric. When vinyl sheet is utilized heating may haveto be extended at low temperatures to avoid degradation of the vinylsheet.

Since thermoforming generally entails forming a heated laminate in acooled mold, the laminate must of course be preheated to thermoformingtemperatures. Such heating is generally affected by passing thelaminates through a heater section in line with thermoforming moldingapparatus. Such heating is generally required to be rapid to avoiddelays in the thermoforming cycle. Such heating is often effected byinfrared radiation heaters where high temperatures at the surface of thelaminate are required to be conducted through the various layers of thelaminate to raise the styrenic foam layers to thermoformingtemperatures. Since such heating is desirably effected as rapidly aspossible, surface temperatures of the laminate may reach adversely highlevels, e.g. to the point of degrading the decorative fabric. Hightemperatures may also be required especially for laminates having largethickness of styrenic foam or multiple layers of styrenic foam. Thepotentially adverse use of high temperatures in heating laminates toavoid delays in thermoforming cycles can be avoided by preheating suchlaminates in ovens at low temperatures, e.g. about 121.degree. C. Suchovens desirably provide indirect heating of the aminates over anextended period of time e.g., two to five minutes, or up to ten minutesor more. Heating to temperatures such that the decorative fabric is notdegraded are of course desired.

For satisfactory thermoforming such laminates can be heated in manycases such that temperature at the interface of the outer layer ofpolyurethane and said styrenic foam is at least about 100.degree. C.when the styrenic foam comprises polystyrene, at least about 105.degree.C. when the styrenic foam comprises styrene-acrylonitrile copolymer, andat least about 115.degree. C. when the styrenic foam comprisesstyrene-maleic anhydride copolymer.

Such preheating can be effected in an oven 10 as shown in FIG. 1, wherea laminate 20 comprising a layer of polyurethane foam 22 adhered to alayer of polystyrene foam 24 is slowly preheated until the temperatureat the interface 26 reaches at least 103.degree. C. The preheatedlaminate can then be readily thermoformed in apparatus 30 as shown inFIG. 2, where an upper mold block 32 has an internal curved surface 34and a lower mold block 36 has an internal curved surface 38.

The preheated laminate 20 is thermoformed to a shape defined by curvedsurfaces 34 and 38. Desirably, mold blocks 32 and 36 will be cooled byan outside source (not shown) to facilitate removing heat from thethermoformed laminate allowing the laminate to retain its thermoformedshape.

The following examples are provided to illustrate the specificembodiments and aspects of the method for thermoforming laminates ofthis invention but are not intended to imply any limitation of the scopeof this invention.

EXAMPLE 1

This example illustrates a method of this invention where the laminateis preheated to thermoforming temperatures in a low temperature ovenover an extended period of time.

A laminate was prepared comprising the following successively adheredlayers:

-   Layer A—an outer layer of polystyrene foam, 0.36 centimeters thick,    having a density of 55 kilograms per cubic meter, and having adhered    to both surfaces an acrylic polymer-impregnated, non-woven,    spunbonded, polyester fabric with a basis weight of 34 grams per    square meter;-   Layer B—an inner layer of polyurethane foam, 0.64 centimeters thick,    and having a density of 18 kilograms per cubic meter;-   Layer C—an inner layer of polystyrene foam, similar to layer A; and-   Layer D—an outer layer of polyurethane foam, 0.38 centimeters thick,    having a density of 25 kilograms per cubic meter, and having adhered    to the outer surface of napped nylon fabric.

The laminate was heated in a 121.degree. C. oven. The temperature at theinterface of Layers C and D rose to 71.degree. C. after two minutes,88.degree. C. after three minutes, and 104.degree. C. after fiveminutes. With the interface temperature at 104.degree. C. the laminatewas readily thermoformed without further heating.

EXAMPLE 2

This example illustrates a method of this invention where the laminateis preheated to thermoforming temperatures by reduced output infraredradiation heaters over an extended period of time.

A laminate was prepared as in Example 1 and preheated for 70 seconds byreduced output infrared radiation heaters. After 70 seconds the topsurface of the laminate, the decorative fabric facing of thepolyurethane foam (layer D), reached a temperature of about 149.degree.C., at which temperature the nylon fabric facing did not degrade. Thelower surface of the laminate, the polymer impregnated fabric coating ofthe polystyrene foam (layer A), reached a temperature of about143.degree. C. The interface of Layers C and D reached a temperature ofabout 104.degree. C. The laminate at such temperatures was readilythermoformed.

EXAMPLE 3

This example illustrates a further method of this invention.

A laminate was prepared comprising a layer of decorative fabric facedpolyurethane foam (similar to layer D of Example 1) adhered to a layerof styrenemaleic anhydride copolymer foam, about 0.38 centimeters thick,and having adhered to both surfaces a dense (0.2 millimeter thick) layerof styrene-maleic anhydride copolymer.

The laminate was preheated to thermoforming temperatures by reducedoutput infrared radiation heaters for 60 seconds. The top surface of thelaminate, the decorative fabric facing of the polyurethane foam, reacheda temperature of about 177.degree. C., at which temperature nylon fabricfacing did not degrade. The bottom surface, the dense layer ofstyrene-maleic anhydride copolymer, reached a temperature of about160.degree. C. The interface between the polyurethane foam and thestyrene-maleic anhydride copolymer foam reached a temperature of about118.degree. C. The laminate at such temperatures was readilythermoformed.

While specific embodiments of the invention have been described, itshould be apparent to those skilled in the art that variousmodifications thereof can be made without departing from the true spiritand scope of the invention. Accordingly, it is intended that the scopeof the following claims cover all such modifications within the fullinventive concept.

APPENDIX IV Two Control Patents A. U.S. Pat. No. 4,627,177 B. U.S. Pat.No. 4,364,189 APPENDIX IV

A. U.S. Pat. No. 4,627,177

U.S. Pat. No. 4,627,177

Meyers Dec. 9, 1986

Insole Structure

Abstract

A footwear insole member comprising a first portion the area of theupper surface of which approximately underlies the area of thelongitudinal arch and a second portion the area of the upper surface ofwhich underlies at least about 10% of the medial area of the heel andfrom 0 to about 50% of the lateral area of the heel, the border of thearea of the upper surface of said second portion including about 10% toabout 65% of the outer edge of the heel area, said first and secondportions being less compressible than the remaining portions of saidmember.

Inventors: Meyers; Stuart R. (2910 Wallace Ave., Bronx, N.Y. 10467)

Appl. No.: 761662

Filed: Aug. 1, 1985

Current U.S. Class: 36/43; 36/91; 36/154

Inter'l Class: A43B 013/38

Field of Search: 36/43,44,31,32 R,88,93,91 128/595,586,614

References Cited [Referenced By]

U.S. Patent Documents 4338734 July, 1982 Schwartz 36/44. 4364188December, 1982 Turner et al. 36/31. 4364189 December, 1982 Bates 36/31.Foreign Patent Documents 129919 October, 1932 AT 128/595. 2709546September, 1978 DE 36/44. 2751146 May, 1979 DE 36/31. 2806481 August,1979 DE 36/31.

Primary Examiner: Kee Chi; James

Attorney, Agent or Firm: Davis Hoxie Faithfull & Hapgood

Parent Case Text

This is a continuation of Ser. No. 626,424, filed on Jul. 2, 1984, nowabandoned, which is a continuation of Ser. No. 438,389, filed on Nov. 1,1982, now abandoned.

Claims

What is claimed is:

1. A footwear insole member comprising a first portion the upper surfaceof which approximately underlies a substantial portion the area of thelongitudinal arch and a second portion the upper surface of whichunderlies at least about 10% of the medial area of the heel and wherethe second portion extends through substantially the whole of the medialheel, contiguously beyond from about 0% to about 50% of the lateral areaof the heel, said first and second portions being contiguous with eachother and being contiguous with and less compressible than the remainingportions of said member, the edges of said first and second portionsadjacent to said remaining portions undercutting said remaining portionsat a downwardly sloping angle of up to about 85.degree. from thevertical to form a wedge which, at its heel end terminus, is entirely inthe medial portion of the heel.

2. A member to claim 1 which comprises elastomeric material.

3. A member according to claim 2 wherein said material comprises amicrocellular foam structure.

4. A member according to claim 3 wherein said structure is open-celled.

5. A member according to claim 3 wherein said structure isclosed-celled.

6. A member according to claim 1 wherein said first and second portionsare predominantly formed of material more dense than the material of theremaining portions of said member.

7. A member according to claim 1 wherein said undercutting edgeshorizontally comprise an approximately S-shaped configuration.

DESCRIPTION

This application is a continuation-in-part of my application Ser. No.196,020 filed Oct. 10, 1980 which is in turn a division of myapplication Ser. No. 970,010 filed Dec. 18, 1978 and now U.S. Pat. No.4,297,797 dated Nov. 3, 1981, the disclosures of which priorapplications and patent are incorporated herein by reference thereto.

The “Background and Description of the Prior Art” in lines 9-55 ofcolumn I of my said patent are applicable to the present application.Reference is also made to the “Reference Cited” in my said patent. Noneof the references referred to in my said patent teach the inventiondisclosed and claimed in said patent or more particularly in thisapplication.

According to the invention described in my said patent, a footwearinsole member is provided comprising a medial portion less compressiblethen the lateral and metatarsal portions whereby the weight of the footundergoing compression in the lateral and metatarsal portionsdynamically forms a medial arch. The member is mainly described asformed of a multiplicity of compressible fluid filled chambers, thevariations in compressibility between the medial portion and theremaining portions being achieved by suitable adjustment or selection ofthe sizes and/or wall thickness and the like of the chambers in therespective portions.

One object of this application and invention is to further elaborate onthe functions and advantages of the device disclosed in my U.S. Pat. No.4,297,797.

Another object of this invention is to provide an insole member which isfurther improved relative to the insole member disclosed and/or claimedin my said patent.

Still another object of this invention is the provision of an insolemember which is more economical and/or simple to make and/or lighter inweight and/or more insulative relative to the insole member of my saidpatent.

Yet a further object of this invention is the provision of an insolemember providing further improvements with respect to comfort,prevention of excessive medial roll of the heel, and/or better or moreefficient biomechanical functions relative to the insole member of mysaid patent.

The attainment of one or more of these and other objects and advantagesis made possible by this invention which comprises a footwear insolemember comprising a first portion the area of the upper surface of whichapproximately underlies the area of the longitudinal arch and a secondportion the area of the upper surface of which underlies at least about10% of the medial area of the heel and from 0 to about 50% of thelateral area of the heel, the border of the area of the upper surface ofsaid second portion including about 10% to about 65% of the outer edgeof the heel area, said first and second portions being less compressiblethan the remaining portions of said member.

The means of such attainment is explained in the following descriptionand the accompanying drawings in which:

FIG. 1 is a plan view from above of a preferred embodiment of a leftfoot insole member of this invention;

FIG. 2 is a medial side view of the insole member of FIG. 1 from thedirection of arrow 2;

FIG. 3 is a lateral side view of the insole member of FIG. 1 from thedirection of arrow 3; and

FIG. 4 is an enlarged end view of the insole member of FIG. 1 from thedirection of arrow 4.

In the several figures of the drawing, like reference charactersindicate like parts of said insole member.

Referring to the upper surface area shown in FIG. 1, and in relation tocorresponding parts of the (lower surface of the) foot, the broken linejoining 10 and 12 generally divides the lateral area of the insolemember (completed by the curvilinear line through 16 and 20) from themedial area of the insole member (completed by the curvilinear linethrough 14 and 18). The area of the metatarsal head and toe portions isgenerally bound by the lines joining 14, 10 and 16 back to 14. The areaA of the longitudinal arch is generally bound by curvilinear lines 18-14and 14-22 and broken lines 22-18. The medial area B and C of the heel isgenerally bound by curvilinear line 18-12 and broken lines 12-24 and24-18. The lateral area D of the heel is generally bound by curvilinearline 20-12 and broken lines 12-24 and 24-20. The outer edge of the heelarea is generally defined by the curvilinear line joining 20, 12 and 18.

According to the invention, the aforesaid area A of the longitudinalarch (first portion) and the area B bound by curvilinear lines 18-26 and26-22 and broken line 22-12 (second portion) generally define the uppersurfaces of the portions of the insole member less compressible (e.g.more dense) than the remaining portions of said member; the area B ofsaid second portion constitutes at least about 10% of the aforesaidmedial area B and C of the heel and from 0 to about 50% of the aforesaidlateral area D of the heel; and the outer border of the area B of saidsecond portion includes about 10% to about 65% (curvilinear line 26-18)of the aforesaid outer edge of the heel area B, C and D. Curvilinearline joining 26, 22 and 14, shown as being approximately S-shaped, marksthe horizontal line of separation between the less compressible portionsunder areas A and B and the remaining portions of the insole member.

FIG. 2 from the medial side shows, according to a preferred embodiment,the upwardly contoured edge of the longitudinal arch, area A. Alsoaccording to a preferred embodiment, the less compressible portion underarea A is shown as undercutting the more compressible portion of themetatarsal area along line 14-30 at a downwardly sloping angle E(measured from the vertical line 14-14′) to form a wedge indicated bythe lines joining 14, 30, and 14′. Angle E shown at 45.degree.,preferably may range up to about 85.degree., more preferably from about20.degree. to about 65.degree.

FIG. 3 from the lateral side shows the upwardly sloping contour of thelongitudinal arch under area A.

FIG. 4 from the heel end also shows the upwardly sloping contour of thelongitudinal arch area A. The less compressible portion under area B isshown as undercutting the more compressible portion under heel area C inthe form of a wedge B′ defined by the lines joining 26, 28 and 26′forming a downwardly sloping angle E′, (measured from the vertical line26-26). Angle E′, shown as about 45.degree., may preferably range up to85.degree., more preferably from about 20.degree. to about 65.degree.,and may be the same as or different from angle E (FIG. 2), i.e. theangle of the undercutting wedge may vary along the S-shaped line26-22-14. Alternatively, the portions under areas A and B may have noundercutting wedge borders, i.e. angles E and E′ would be 0.degree.

It will be understood that within the scope of my invention variationswithin the several aforesaid ranges of angles, area values, sizes andpositions, etc., and modifications of the preferred embodiments shown,for illustrative purposes only, in the drawing will become obvious, andin some instances advisable or even necessary, to those skilled in theart. By way of example, and depending upon such factors as the type,foot size, foot shape, foot sensitivity, age, etc. of the user, the typeof footwear, the activity contemplated, etc., points 16, 20, 26, 18 and14 may be shifted as deemed advisable in either direction along theperiphery of the insole member, the shape and location of the line26-22-14 may be changed or even rendered non S-shaped, e.g., itsintersection at 22 may be shifted in either direction along line 18-20,it may curve into the lateral area, and/or its terminus at 14 may notcoincide with the line 16-14 demarking the inner edge of the metatarsalarea, the shape and size of the insole member may be varied, etc.

Preferably but not necessarily the lower or bottom surface of the insolemember is essentially planar (it may be transversely or longitudinalgrooved or ridged) and its upper surface is contoured in approximateconformance with the bottom surface of the foot, and the thickness ofthe insole member may vary from about ⅛″ to about 1.5″, preferablygenerally decreasing from heel to toe and from medial arch to lateralside with suitable cupping in such areas as the heel, lateral side andball of the foot. The insole member of this invention may be providedfor insertion into existing footwear or it may be made part of theoriginal construction of the footwear.

An essential feature of this invention involves the use of more or lesscompressible or resilient material. This material may be natural orsynthetic and solid (non-cellular) or cellular (e.g. foam, sponge,microcellular, macrocellular, honeycombed). The degree ofcompressibility of these materials may be controlled, adjusted andpredetermined in known matter, e.g. density, cell size, cell wallthickness, degree of polymerization and/or cross-linking, etc. Generallyelastomeric, examples of such material include latex, natural rubber,butyl rubber, BSR (butadiene/styrene rubber), ABS rubber(acrylonitrile/butadiene/styrene terpolymer), polyurethane, otherplastics, copolymers and interpolymers thereof, etc. A microcellularfoam structure is preferred which may be closed celled or open-celled(permitting transfer of fluid between cells with shock-absorbing effectunder weight-bearing conditions. The cellular material may contain anysuitable fluid in its cells, e.g. air or any other gas or water or anyother suitable liquid. A polyurethane microcellular foam material ispreferred. The less compressible (less resilient, more rigid, etc.)portions in the longitudinal arch and medial heel areas (A and B in thedrawing) may be the same or different in chemical composition andphysical structure from the remaining portions of the insole member, andare preferably (but not necessarily) contiguous with each other (betweenthe A and B portions and/or between those portions and the remainingmore compressible portions, as shown in the drawing. The A and Bportions may be more densed, contain smaller cells and/or thicker cellwalls, and/or made of an entirely different less compressible materialrelative to the remaining portions of the insole member.

The insole member may be made in any suitable manner, as by injectionmolding (double injection, biphase single injection) vacuum or blowmolding, etc. using suitable elastomeric material. The A and B portionsmay be bonded to each other and/or to the remaining portions of theinsole member during the molding or other forming operation, or they maybe separately made and then assembled by suitable bonding at theirperipheries by means of heat and/or adhesive, etc., or without bondingon a sheet material (disposable or permanent).

The insole member of this invention provides a heretofore unattainabledynamic biomechanical system yielding multiple unexpected advantages infoot and gait control. This system permits the lateral column of thefoot to depress in a piston-like action with each step, controlsinternal torque from the leg (in the first portion of the gait cycle),and redirects the torque of the leg in an external direction by allowingthe lateral column of the foot to depress and invert (2nd portion of thegait cycle, slightly before midstance). The novel structure of thisinsole member for example (1) prevents excessive medial roll of the heelin the first portion of the gait cycle so as to function as a tri planewedge, and (2) it forces the heel and lateral column of the foot toinvert on full weight bearing (as approaching the midstance phase of thegait), thereby stabilizing the foot making it a rigid lever for thepropulsive phase of the gait. It provides a piston-like action underweight bearing with each step so that there is a constant return to itsoriginal shape after weight-bearing has ceased. It provides a mechanicaladvantage to the subtalar joint toward supination so that lowering ofthe lateral column will occur more efficiently and sooner in the gaitcycle. The foot therefore becomes a rigid lever at the time it is neededin the gait cycle when full body compression occurs. It limits excessivepronation in the initial portion of the gait cycle and preventsexcessive excursion of the posterior calcaneal facet (heel acticulation)thereby preventing excessive migration of the talus (ankle bone) off thecalcanaus (heel bone). Since the subtalar joint and the midtarsal jointcan only move either clockwise or counter clockwise, the medial contacton the less compressible area will cause the heel to invert, causing thelateral column of the foot to depress and invert. This causes themidtarsal joint to move antagonistically to the supinating subtalarjoint and pronate maximally thereby stabilizing the foot. The systemallows the plantar fascia to act as a more efficient truss system inmetatarsal plantar flexion and stability. It also allows the muscles tofunctionally contract at mechanical advantages for optimum footmechanics.

The insole member of this invention is useful in all types of footwear,therapeutic or not, work or play, inactive or active, including forexample all types of athletic shoes and boots, walking, jogging andrunning shoes, army boots, ski shoes, climbing boots, sneakers,slippers, etc.

The invention has been disclosed with respect to preferred embodiments,and various modifications and variations thereof obvious to thoseskilled in the art are to be included within the spirit and purview ofthis invention and the scope of the appended claims.

APPENDIX IV

B. U.S. Pat. No. 4,364,189

U.S. Pat. No. 4,364,189

Bates Dec. 21, 1982

Running shoe with differential cushioning

Abstract

A sports running shoe constructed to minimize impact shock and tomaximize lateral stability. The shoe's midsole is formed with a mediallayer portion having one overall firmness, and a lateral layer portionhaving a lesser overall firmness.

Inventors: Bates; Barry T. (3809 Monroe St., Eugene, Oreg. 97405)

Appl. No.: 213207

Filed: Dec. 5, 1980

Current U.S. Class: 36/31; 36/29; 36/30R; 36/37; 36/129

Intern'Class: A43B 013/16; A43B 021/32; A43B 005/00

Field of Search: 36/31,32 R,30 R,43,44,37,29,129,114 128/581,583-585

References Cited [Referenced By]

U.S. Patent Documents 1428356 September, 1922 Brown. 1432961 October,1922 Brown. 2001821 May, 1935 Everston 36/28. 2099418 November, 1937Bradley et al. 36/11. 2678506 May, 1954 Baroumes 36/8. 2694871 November,1954 Rollman 36/14. 2983056 May, 1961 Murawski 36/29. 3594929 July, 1971Stohr 36/44. 3892077 July, 1975 Wolstenholme et al. 36/44. 4079526March, 1978 Fukuoka 36/30. 4180924 January, 1980 Subotnick 36/129.4187621 February, 1980 Cohen 36/44. 4235026 November, 1980 Plagenhoef36/32. 4236326 December, 1980 Inohara 36/29. 4302892 December, 1981Adamik 36/31. Foreign Patent Documents 2709546 September, 1978 DE 36/44.2751146 May, 1979 DE 36/31. 2806481 August, 1979 DE 36/31. 2904540August, 1980 DE 36/129. 828437 February, 1938 FR 36/32.

Primary Examiner: Kee Chi; James

Attorney, Agent or Firm: Kolisch, Hartwell & Dickinson

Claims

It is claimed and desired to secure by Letters Patent:

1. Sole means in a sports shoe for absorbing shock on impact, and forproducing lateral foot stability when the shoe is used for running, saidmeans comprising

-   a heel section formed of a resilient material whose overall firmness    on the inner side of a longitudinal heel midline axis is greater    than that on the outer side of said midline axis, and-   a forefoot section formed of a resilient material whose overall    firmness on the outer side of a longitudinal forefoot midline axis    is substantially the same as that on the outer side of said heel    midline axis in said heel section.

2. Sole means in the heel region of a sports shoe for absorbing shock onimpact, and for producing lateral foot stability when the shoe is usedfor running, said means comprising

-   a first elastomeric slab portion having one density and having its    mass distributed primarily on the medial side of the midline axis in    such heel region, and-   a second elastomeric slab portion having another density which is    less than said first density and having its mass distributed    primarily on the lateral side of said midline axis.

3. The sole means of claim 2, wherein said slab portions are located ina midsole for the shoe, and meet along a planar interface substantiallycontaining said midline axis.

4. The sole means of claim 3, wherein, with the shoe in an operativeposition, the plane containing said interface is substantially vertical.

5. The sole means of claim 3, wherein, with the shoe in an operativeposition, the plane containing said interface slopes downwardlyprogressing toward the outer side of the shoe.

Description BACKGROUND AND SUMMARY

The present invention relates to sports shoes, and in particular, to arunning shoe constructed to minimize impact shock and to maximizelateral stability.

Extensive clinical evaluation of foot and knee injuries sustained byrunners and joggers suggests that the most important factors associatedwith such injuries are shock absorption on impact and lateral footstability. Based on injury data, these two factors appear to be of aboutequal importance. Therefore, both factors should be considered inproposing improvements in sports shoes.

For most runners, initial foot impact occurs in the heel region. Heelcushioning material, which is contained principally in the shoe'smidsole of a running shoe has a firmness which provides proper impactcushioning for a person of about average weight. Where the runner isquite heavy, the heel cushioning material may “bottom out” before heelimpact is completely absorbed, and shock-related injuries can result. Onthe other hand, poor lateral foot stability may result in conventionallyconstructed running shoes if the cushioning material is too soft.

Lateral foot stability refers to a shoe's ability to control the normaltendency of a foot to roll toward its inside on impact. Ideally thisinward rolling of the foot, which is known as pronation, is arrestedabout when the knee is maximally flexed. Where the foot continuespronation after the knee reaches its maximum flexion and has begun tostraighten, cumulative knee strain leading to knee injury may occur. Asa general rule, prior art running shoes having a relatively firmmidsole, particular in the heel region, provide the best lateralstability.

One general object of the present invention is to provide a running shoehaving both good shock absorption and lateral stability characteristics.

A more specific object is to provide such a shoe in which the runner'sweight, during initial impact, is transferred from softer to firmercushioning material, to provide effective shock absorption in both lightand heavy runners.

Still another object is to provide such a shoe which is constructed toincrease lateral foot stability without sacrifice in shock absorptioncharacteristics.

The sports shoe of the present invention includes a sole layer which isformed of an inner side layer portion having one overall firmness and anouter side layer portion having a lesser overall firmness. In oneembodiment of the invention, the layer portions are locatedsubstantially in the heel region of the layer. In another embodiment,such portions extend substantially throughout the length of the layer.

These and other objects and features of the present invention willbecome more fully apparent when the following detailed descriptions ofpreferred embodiments of the invention are read in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a side view of a sports shoe having a midsole constructedaccording to one embodiment of the present invention;

FIG. 2 illustrates, in top plan view, the midsole of the shoe of FIG. 1,removed from the shoe;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1 furtherillustrating the shoe's midsole with the same joined to an outsole;

FIG. 4 is a view similar to FIG. 3 showing another embodiment of arunning shoe midsole as contemplated by the present invention;

FIG. 5 is a view similar to FIG. 2, illustrating still anotherembodiment of a midsole contemplated by the present invention;

FIG. 6 is a side view, similar to FIG. 1, showing a sports shoe having amidsole constructed in accordance with yet another embodiment of thepresent invention; and

FIG. 7 is a view similar to FIG. 2 illustrating, in top plan view, themidsole of the shoe of FIG. 6, removed from the shoe.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 there is shown at 10 a sports shoe constructed according toone embodiment of the invention. Shoe 10 includes a soft foot covering11 secured to the upper surface of a midsole 12 which joins on itsbottom side with an outsole 16. The outsole includes on its base aconventional pattern of generally wedge-shaped lugs, such as lugs 17,which are separated by generally wedge-shaped spaces.

With reference to FIGS. 2 and 3, the shoe, and particularly midsole 12has an outer, or lateral, side 20 and an inner, or medial, side 22. Whatmight be thought of as an angled longitudinal midline axis in the shoe,indicated by dash-dot line 24 in FIG. 2, extends along the length of theshoe substantially midway between sides 20, 22. Axis 24 includes a heelaxis segment 24a which substantially bisects the heel region of theshoe, here indicated at 26, and a forefoot axis segment 24bsubstantially bisecting the forefoot region of the shoe, which isindicated in FIG. 2 at 28. The shoe expanses on outer and inner sides ofaxis 24 (upper and lower sides of this axis in FIG. 2) are denotedherein as outer and inner lateral side expanses 30, 32, respectively.

Midsole 12 includes an elastomeric slab portion 34 having the planarshape indicated by cross-hatch shading in FIG. 2, and correspondingroughly to the inner side expanse in the heel region of the shoe.Portion 34, as it appears from the side of the shoe, is indicated alsoby cross-hatch shading in FIG. 1. As can be appreciated in FIG. 3, theinterior edge of portion 34 occupies a vertical plane with the shoe inits normal position, with this plane containing axis segment 24a.

Portion 34, which is also referred to herein as an inner resilient layerportion, is preferably formed of a foamed elastomeric material such aspolyurethane. The overall firmness in such material is generallydirectly related to the material's density. A typical density in portion34 is one which produces an overall firmness, as measured by aconventional durometer scale of between about 70 and 80-Shore.

Forming the remainder of midsole 12 are upper and lower somewhatL-shaped midsole layers 36, 38, respectively. Layer 36, which has theplanar shape shown by the unshaded region of the midsole in FIG. 2,tapers in thickness toward a front end 39 adjacent the toe of the shoe,as can be seen in FIG. 1. Layer 38, which terminates at a forward end 40in FIGS. 1 and 2, has the same planar dimensions as that portion oflayer 36 which is to the right of end 40 in FIG. 2. Referring to FIG. 3,the interior edges of layers 36, 38, in the heel region of the shoe,abut layer 34 along the above-mentioned vertical plane. The portions oflayers 36, 38 coextensive with portions 34 in the heel section of theshoe are also referred to herein, collectively, as an outer resilientlayer portion and as an elastomeric slab portion.

Midsole layers 36, 38 are preferably formed of a foamed elastomericmaterial such as polyurethane. According to an important feature of theembodiment of the invention now being described, layers 36, 38,particularly in the heel region of the shoe, have an overall firmnesswhich is substantially less than that of portion 34. Specifically,layers 36, 38 have densities which produce durometer readings in therange of between about 30 and 35-Shore and about 35 and 45-Shore,respectively. It should be recalled that the durometer reading forportion 34 is about twice these values.

Let us consider now how shoe 10 performs. Perhaps a good way to beginthis explanation is to describe generally the mechanics of a “typical”running footfall, and to explain what is meant by shock absorption andlateral stability. The term “typical”, as used in the precedingsentence, was placed in quotation marks to reflect the fact that no twofootfalls, even with the same runner, are exactly identical.

Considering the fall of a person's right foot during running, thefootfall begins with an impact (through a shoe) between the underlyingsurface and the lateral side of a person's heel. As the footfallprogresses, there is an inward rolling of the foot, relative to the axisof the leg, toward the medial side of the foot, and there is a furtherimpact between the underlying surface and the forefoot region of thefoot. Thereafter, the foot continues by lifting from the surface.

Shock to the foot, ankle, and leg is considered herein to besubstantially vertically directed, and is directly proportional to therate of vertical deceleration which the foot experiences during afootfall. Sequential impacting of first the lateral heel region in afoot, and thereafter the forefoot region, results in what might bethought of as a dual-peak shock-transmission situation. In other words,vertical foot deceleration tends to maximize in concurrence with thesetwo events.

Accordingly, shock absorption and reduction is directly attainable byminimizing the peaks in such peak deceleration.

After the foot has first struck the ground, and when the same beginspronation, there occurs a somewhat oscillatory lateral forcetransmission between the foot and the underlying surface. In otherwords, such force transmission will at one moment be directed laterallyoutwardly, and in another moment medially, and so on. The kind oflateral instability which is considered to be potentially damaging, andwhich is sought to be avoided, results directly from the degree ofpronation which occurs. The greater the amount of pronation, the greaterthe energy which is absorbed angularly in the ankle, the lesser is thelateral force transmission to the underlying surface, and the greaterthe instability. Conversely, the lower the amount of pronation, thelower the amount of energy angularly which is absorbed in the ankle, thegreater is the force transmission to the underlying surface, and thegreater is the stability. Thus, an effort to maximize lateral stabilityis one which seeks to minimize pronation and to maximize lateral forcetransmission to the ground during a footfall.

From the discussion above, it will be apparent that the performance of ashoe during running to minimize shock and lateral stability can beevaluated from force measurements which are made during a runner'sfootfalls. In a manner which will now be described, such measurementshave been made in rather substantial detail with respect to a shoeconstructed like shoe 10, as well, in a comparative sense, with respectto several currently available conventional running shoes.

The testing data which appears in the tables below was obtained from theperformances of five different subjects, all of them regular runners,wearing each of four different types of shoes. The shoes in the tablesare simply identified by Arabic numbers. Shoe-1 was one manufactured byOsaga, Inc., 2468 West 11 th, Eugene, Oreg., identified as a modelnumber KT-26. Shoe-2 was exactly the same shoe, except that it wasmodified in its midsole in accordance with the description above ofmidsole 12 in shoe 10. Shoe-3 was one manufactured by Nike, Inc.,Beaverton, Oreg., and sold under the trade designation Tailwind. Shoe-4was one made by Adidas, Sportschuhfabricken, 8522 Herzogenaurach, WestGermany, Postfach 1120, sold as model number TR-X.

The experimental set up for obtaining data included a conventional forceplatform interfaced in a well known manner with a conventional computerand with a suitable graphics display system. An acceptable test requiredthat each runner contact the force platform in a normal stride patternat a designated pace, which was controlled between a 6½ and a 7½ minutemile pace using a photoelectric timing system. Platform contact forcerecording was triggered automatically by the computer.

Tables, I, II and III below relate to shock absorption. Table I, whichis entitled “First Maximum Vertical Force Values”, includes dataobtained from initial lateral heel impact with the platform. Table II,which is labeled “Second Maximum Vertical Force Values”, reflects dataobtained from forefoot region impact with the platform. Table III showsaverage vertical force values throughout the total foot platform contactperiod. The force values presented in these three tables are innormalized units of Newton's per kilogram of subject body mass. TABLE IFirst Maximum Vertical Force Values Subject Shoe-1 Shoe-2 Shoe-3 Shoe-41 20.3 13.4 20.0 11.3 2 17.6 17.4 19.5 18.0 3 12.8 11.5 13.0 12.1 4 15.216.1 13.1 17.1 5 15.2 15.2 16.1 12.8 Mean 16.4 14.7 16.3 14.3

TABLE II Second Maximum Vertical Force Values Subject Shoe-1 Shoe-2Shoe-3 Shoe-4 1 27.8 15.8 26.0 15.1 2 25.1 25.0 26.4 26.2 3 14.0 11.914.9 14.2 4 14.1 14.1 12.5 17.6 5 25.1 24.4 24.3 24.2 Mean 21.2 18.220.8 19.5

TABLE III Average Vertical Force Values for Total Support Period SubjectShoe-1 Shoe-2 Shoe-3 Shoe-4 1 15.5 8.7 14.3 8.6 2 14.7 14.3 15.4 15.5 38.0 6.8 8.7 8.3 4 8.2 8.3 7.5 10.6 5 14.2 14.0 14.4 14.2 Mean 12.1 10.412.0 11.4

In each column of Tables I, II and III, which column pertains to aparticular one of the four different tested shoes, there are six datanumbers. The first five are the normalized force values measured foreach of the five different runners. The sixth and lowest number in eachcolumn is the mean number for the column. Referring particularly to themean numbers presented in these three tables, in table I it is seen thatshoes 2 and 4 are closely competitive, and are significantly betterheel-impact shock absorbers than shoes 1 and 3. In Table II, the meannumbers clearly indicates superiority of shoe-2 for forefoot impactshock absorption.

The average mean values presented in Table III confirm shoe-2 as beingsuperior in overall shock-absorption characteristics.

Tables IV and V below relate to lateral stability. Table IV which isentitled “Average Medial/Lateral Force Values for 15-45% of SupportPeriod” indicates the direction and magnitude of maximum normalizedside-directed forces occuring during the first 15%-45% of the total footcontact time. Table V which is entitled “Average Medial/Lateral ForceValues for 30-60% of Support Period” is similar to Table IV, except thatit relates to a different particular span of the overall foot-contacttime period. TABLE IV Average Medial/Lateral Force Values for 15-45% ofSupport Period Subject Shoe-1 Shoe-2 Shoe-3 Shoe-4 1 −70 −50 −29 −5 2 4−48 −95 −44 3 52 71 45 63 4 −35 −40 4 −24 5 5 −4 48 44 Mean −9 −14 −5 7

TABLE V Average Medial/Lateral Force Values for 30-60% of Support PeriodSubject Shoe-1 Shoe-2 Shoe-3 Shoe-4 1 −157 −116 −104 −78 2 −49 −104 −170−134 3 −28 −22 −57 −41 4 −99 −92 −90 −120 5 −27 −22 −4 −5 Mean −68 −71−85 −56

It can be seen that in these two tables both positive and negative forcevalues are recorded. The algebraic signs of these values is simply anindication of the direction in which the recorded forces were applied.

Recalling that maximum lateral force transmission indicates minimalpronation and maximum lateral stability, Table IV, and with reference tothe mean force values presented in this table, indicates clear lateralstability superiority in shoe-2. In Table V, shoe-3 appears to besomewhat superior to shoe-2, with both of these shoes being superior inlateral stability performance vis-a-vis shoes 1 and 4.

What the data in these two tables indicates is that, shoe-2 providessignificant lateral stability in comparison with the other tested shoes.

Recognizing, as one must, that there is no single running-shoe designwhich is superior in all respects under all conditions for all runners,test data developed in the comparisons just discussed indicates that ashoe constructed along the lines of shoe 10 tends to produce overallbetter-shoe performance. In other words, such construction tends tomaximize both shock absorption and lateral stability.

Continuing with a description of what is shown in the drawings, FIG. 4illustrates, in a cross-sectional view similar to that presented in FIG.3, a midsole 41 constructed in accordance with another embodiment of theinvention. As in FIG. 3, the medial side of the midsole is on the rightside of FIG. 4. The heel region in midsole 41 is formed of a pair ofslab portions 42, 44 having the cross-sectional shapes illustrated inFIG. 4, with each slab having substantially the same longitudinalextents as portion 34 in FIG. 2. Slab portions 42, 44 meet along aplanar interface which slopes downwardly toward the outer side of theshoe. Portion 42 has a density and firmness similar to that of portion34. Portion 44 has a density and firmness similar to those of previouslymentioned layers 36, 38.

A shoe constructed in accordance with FIG. 4 performs with substantiallythe same overall improved shock absorption and lateral stabilitycharacteristics described above for shoe 10.

FIG. 5 shows a midsole 46 constructed according to yet anotherembodiment of the invention. In midsole 46, a slab portion 48, similarin firmness and density to previously mentioned portion 34 in midsole12, extends along the full length and depth of the midsole. This portionis distinguished in FIG. 5 by cross-hatch shading. The unshaded portionof midsole 34 has a density and firmness similar to those of layers 36,38 in midsole 12.

A shoe constructed in accordance with FIG. 5 also performs, in anoverall sense, with greatly enhanced shock absorption and lateralstability characteristics.

Describing now still another modification of the present invention, thesame is shown in FIGS. 6 and 7. In FIG. 6, a shoe, which is similar inmany respects to shoe 10, is shown generally at 50. Like shoe 10, shoe50 includes a soft foot covering 52 secured to the upper surface of amidsole 54 which joins, on its bottom side, with an outside 56. Outsole56 is like previously described outsole 16.

As distinguished from the above-described embodiments of a running shoe(according to the invention), whereas differential firmness in theseprior-described shoes is achieved through the utilization of slab-likecomponents of different firmness to form a midsole, in midsole 54,firmness differentiation is achieved through providing a unitaryhomogeneous sole member, or web, 58, in the heel region of the shoe,with this member, on its medial side, having a plurality ofsubstantially horizontally inwardly directed bores, such as bores 60.Fitted in bores 60 are cylindrical plugs, such as plugs 62, that have afirmness which is greater than that of the material forming member 58.As can be seen with reference to FIG. 7, midsole 54 includes an angledlongitudinal midline axis 64 which is like previously mentioned axis 24in midsole 12. Axis 54 includes a heel axis segment 64a whichsubstantially bisects the heel region of the midsole. Bores 60 and 62extend substantially from the medial side of the midsole to a verticalplane containing axis segment 64a.

One of the advantages of the construction illustrated in FIGS. 6 and 7is that it offers a high degree of flexibility in forming shoes toaccommodate the needs of different runners. More specifically, thepreparation of a homogeneous midsole piece which includes bores toreceive resilient plugs of differing firmnesses enables a selection tobe made at the time that shoe is purchased of the appropriate plugs tosuit a runner's requirements. Shoe 50 performs with all of theadvantages described earlier with respect to the other shoe embodimentsherein.

While several embodiments of the invention have been shown and describedherein, it will be appreciated by those skilled in the art thatvariations and modifications may be made without departing from thespirit of the invention.

APPENDIX V Raw Frequency/Weight Data

A. Data for Appendix II —U.S. Pat. No. 4,524,037 (Prior ArtReference-Marc)

B. Data for Appendix IA, U.S. Pat. No. 4,980,110 (Issued Patent)

C. Data for Appendix IB, U.S. Pat. No. 5,273,702 (Issued Patent)

D. Data for Appendix III, U.S. Pat. No. 4,595,551 (Cited as Reference inIssued Patents—Maurer)

E. Data for Appendix IVA-U.S. Pat. No. 4,627,177 (Control)

F. Data for Appendix IVB—U.S. Pat. No. 4,364,189 (Control)

APPENDIX V

A. Data for Appendix 1—U.S. Pat. No. 4,524,037 (Prior ArtReference—Marc)

(1) Data Used in

Exemplary Semantic

Analysis Concept Weight Synonyms apparatus for 14 Forming forming cavity42 compression 10 ratio electrode 7 general 39 heating 95 heating period63 material 87 material 89 compressed means 70 method for method formingplastic 15 polyolefin styrenic resilient material rf heating 89substance 60 temperature 77

(2) Composite and Specific Frequency/Weight Data Concept FrequencyWeight Subordinate Concept apparatus for 7 14 ========== forming cavity10 42 ========== compression ratio 2 10 ========== electrode 3 7========== general 2 39 ========== heating 4 95 ========== heatingperiod 2 63 ========== material 23 87 ========== material 2 89========== compressed means 8 70 ========== plastic 6 15 ========== rfheating 2 89 ========== substance 3 60 ========== temperature 4 77========== material 4 58 apparatus for forming plastic 6 100 apparatusfor forming general 2 79 cavity material 3 47 cavity means 3 69 cavitysubstance 3 89 cavity material 2 32 compression ratio means 2 51electrode cavity 2 47 general material 2 32 general substance 2 71general heating period 2 79 heating material 3 47 heating material 2 79heating compressed means 2 51 heating rf heating 2 79 heatingtemperature 2 65 heating heating 2 65 heating period material 2 32heating period means 2 51 heating period apparatus for 4 82 materialforming cavity 3 64 material compression ratio 2 79 material general 279 material heating 3 83 material heating period 2 79 material material2 79 material compressed means 4 79 material plastic 4 86 material rfheating 2 79 material substance 3 89 material temperature 2 65 materialheating 2 65 material compressed material 2 32 material compressed rfheating 2 79 material compressed temperature 2 65 material compressedcavity 3 64 means electrode 2 71 means heating 2 65 means heating period2 79 means material 4 58 means substance 2 71 means apparatus for 6 96plastic forming material 4 58 plastic heating 2 65 rf heating material 232 rf heating material 2 79 rf heating compressed temperature 2 65 rfheating cavity 3 64 substance general 2 79 substance material 3 47substance means 2 51 substance heating 2 65 temperature material 2 32temperature material 2 79 temperature compressed rf heating 2 79temperature

APPENDIX V

B. Data for Appendix IIA, U.S. Pat. No. 4,980,110 (Issued Patent 1)

(1) Data Used in

Exemplary Semantic

Analysis Concept Weight Synonyms carrying 4 cavity 94 closing 70 cutting90 density 4 energy 90 fastening 5 fastening 5 means flashing 8 forming82 apparatus for thermoforming forming forming cavity 90 heating 69indicium 6 means 5 method 80 method for 92 forming parting 97 peripheral93 outer peripheral 96 parting polyolefin 80 Plastic styrenic polyolefinbeing 22 sufficient 48 sufficient period 15 temperature 77 two 4

(2) Composite and Specific Frequency/Weight Data Conc pt FrequencyWeight Subordinate Concept carrying 2 4 ========== cavity 13 94========== closing 7 70 ========== cutting 2 90 ========== density 4 4========== energy 2 90 ========== fastening 5 5 ========== fastening 3 5========== means flashing 2 8 ========== forming 6 82 ========== formingcavity 2 90 ========== heating 12 69 ========== indicium 5 6 ==========means 5 5 ========== method 26 80 ========== method for 3 92 ==========forming parting 7 97 ========== peripheral 8 93 ========== peripheral 496 ========== parting polyolefin 18 80 ========== polyolefin being 2 22========== sufficient 13 48 ========== sufficient period 4 15 ==========temperature 6 77 ========== two 2 4 ========== method 2 30 carryingclosing 4 82 cavity cutting 2 79 cavity energy 2 79 cavity flashing 2 79cavity forming 3 75 cavity forming cavity 2 79 cavity heating 6 85cavity method 6 69 cavity method for 3 89 cavity forming parting 6 96cavity peripheral 5 87 cavity peripheral 4 94 cavity parting polyolefin5 70 cavity polyolefin being 2 79 cavity sufficient 5 77 cavitysufficient period 2 65 cavity temperature 6 100 cavity cavity 4 69closing heating 6 85 closing method 4 55 closing parting 4 82 closingperipheral 2 51 closing peripheral 2 65 closing parting polyolefin 3 52closing sufficient 3 59 closing temperature 3 75 closing cavity 2 42cutting energy 2 79 cutting forming 2 57 cutting forming cavity 2 79cutting method 2 30 cutting method for 2 71 cutting forming parting 2 54cutting peripheral 2 51 cutting peripheral 2 65 cutting partingpolyolefin 2 36 cutting method 2 30 density cavity 2 42 energy cutting 279 energy forming 2 57 energy forming cavity 2 79 energy method 2 30energy method for 2 71 energy forming parting 2 54 energy peripheral 251 energy peripheral 2 65 energy parting polyolefin 2 36 energyfastening 3 89 fastening means means 3 78 fastening method 3 45fastening fastening 3 78 fastening means means 3 78 fastening meansmethod 3 45 fastening means cavity 2 42 flashing method 2 30 flashingcavity 3 59 forming cutting 2 79 forming energy 2 79 forming formingcavity 2 79 forming method 4 55 forming method for 3 89 forming formingparting 3 71 forming peripheral 3 69 forming peripheral 2 65 formingparting polyolefin 3 52 forming cavity 2 42 forming cavity cutting 2 79forming cavity energy 2 79 forming cavity forming 2 57 forming cavitymethod 2 30 forming cavity method for 2 71 forming cavity formingparting 2 54 forming cavity peripheral 2 51 forming cavity peripheral 265 forming cavity parting polyolefin 2 36 forming cavity cavity 6 83heating closing 6 96 heating method 6 69 heating parting 4 82 heatingperipheral 2 51 heating peripheral 2 65 heating parting polyolefin 4 63heating sufficient 7 88 heating sufficient period 4 94 heatingtemperature 5 94 heating method 2 30 indicium polyolefin 2 36 indiciumfastening 3 78 means fastening 3 89 means means method 3 45 meanscarrying 2 79 method cavity 6 83 method closing 4 82 method cutting 2 79method density 2 65 method energy 2 79 method fastening 3 78 methodfastening 3 89 method means flashing 2 79 method forming 4 86 methodforming cavity 2 79 method heating 6 85 method indicium 2 60 methodmeans 3 78 method method for 3 89 method forming parting 5 90 methodperipheral 3 69 method peripheral 2 65 method parting polyolefin 9 89method polyolefin being 2 79 method sufficient 5 77 method sufficientperiod 2 65 method temperature 3 75 method two 2 79 method cavity 3 59method for forming cutting 2 79 method for forming energy 2 79 methodfor forming forming 3 75 method for forming forming cavity 2 79 methodfor forming method 3 45 method for forming parting 3 71 method forforming peripheral 3 69 method for forming peripheral 2 65 method forforming parting polyolefin 3 52 method for forming cavity 6 83 partingclosing 4 82 parting cutting 2 79 parting energy 2 79 parting forming 375 parting forming cavity 2 79 parting heating 4 71 parting method 5 63parting method for 3 89 parting forming peripheral 5 87 partingperipheral 4 94 parting parting polyolefin 5 70 parting polyolefin being2 79 parting sufficient 2 42 parting temperature 4 86 parting cavity 577 peripheral closing 2 54 peripheral cutting 2 79 peripheral energy 279 peripheral forming 3 75 peripheral forming cavity 2 79 peripheralheating 2 43 peripheral method 3 45 peripheral method for 3 89peripheral forming parting 5 90 peripheral peripheral 4 94 peripheralparting polyolefin 3 52 peripheral sufficient 2 42 peripheraltemperature 3 75 peripheral cavity 4 69 peripheral parting closing 2 54peripheral parting cutting 2 79 peripheral parting energy 2 79peripheral parting forming 2 57 peripheral parting forming cavity 2 79peripheral parting heating 2 43 peripheral parting method 2 30peripheral parting method for 2 71 peripheral parting forming parting 482 peripheral parting peripheral 4 79 peripheral parting polyolefin 2 36peripheral parting sufficient 2 42 peripheral parting temperature 2 57peripheral parting cavity 5 77 polyolefin closing 3 71 polyolefincutting 2 79 polyolefin energy 2 79 polyolefin forming 3 75 polyolefinforming cavity 2 79 polyolefin heating 4 71 polyolefin indicium 2 60polyolefin method 9 81 polyolefin method for 3 89 polyolefin formingparting 5 90 polyolefin peripheral 3 69 polyolefin peripheral 2 65polyolefin parting polyolefin being 2 79 polyolefin temperature 3 75polyolefin cavity 2 42 polyolefin being method 2 30 polyolefin beingparting 2 54 polyolefin being polyolefin 2 36 polyolefin being cavity 577 sufficient closing 3 71 sufficient heating 7 90 sufficient method 563 sufficient parting 2 54 sufficient peripheral 2 51 sufficientperipheral 2 65 sufficient parting sufficient period 4 94 sufficienttemperature 4 86 sufficient cavity 2 42 sufficient period heating 4 71sufficient period method 2 30 sufficient period sufficient 4 69sufficient period cavity 6 83 temperature closing 3 71 temperatureheating 5 79 temperature method 3 45 temperature parting 4 82temperature peripheral 3 69 temperature peripheral 2 65 temperatureparting polyolefin 3 52 temperature sufficient 4 69 temperature method 230 two

APPENDIX V

C. Data for Appendix IIB, U.S. Pat. No. 5,273,702 (Issued Patent 2)

(1) Data Used in

Exemplary Semantic

Analysis Concept Weight Synonyms carrie integral fastening 4 meanscavity 94 closing 36 cutting 93 density 7 excess 5 forming 89 apparatusfor forming forming cavity 93 ft 4 greater density 8 heating 60 lb 4method 81 method for forming 95 Means nonfoamed 5 organic polymer 5parting 96 peripheral 94 peripheral parting 96 polyethylene 8 polyolefin78 Plastic polyolefin being 8 steps 94 sufficient 18 sufficient period 8sufficient temperature 17 temperature 72

(2) Composite and Specific Frequency/Weight Data Concept FrequencyWeight Subordinat Concept carrie integral fastening 2 4 ========== meanscavity 12 94 ========== closing 6 36 ========== cutting 2 93 ==========density 8 7 ========== excess 2 5 ========== forming 5 89 ==========forming cavity 2 93 ========== ft 4 4 ========== greater density 2 8========== heating 14 60 ========== lb 4 4 ========== method 26 81========== method for forming 3 95 ========== nonfoamed 2 5 ==========organic polymer 2 5 ========== parting 7 96 ========== peripheral 8 94========== peripheral parting 4 96 ========== polyethylene 2 8========== polyolefin 21 78 ========== polyolefin being 2 8 ==========steps 5 94 ========== sufficient 15 18 ========== sufficient period 3 8========== sufficient temperature 6 17 ========== temperature 10 72========== method 2 30 carrie integral fastening means closing 3 75cavity cutting 2 79 cavity forming 3 78 cavity forming cavity 2 79cavity heating 5 75 cavity method 4 55 cavity method for forming 3 89cavity parting 5 90 cavity peripheral 5 87 cavity peripheral parting 494 cavity polyolefin 6 73 cavity steps 4 89 cavity sufficient 2 39cavity sufficient period 2 71 cavity temperature 4 75 cavity cavity 3 60closing heating 4 68 closing parting 3 71 closing peripheral 2 51closing peripheral parting 2 65 closing temperature 2 47 closing cavity2 43 cutting forming 2 60 cutting forming cavity 2 79 cutting method 230 cutting method for forming 2 71 cutting parting 2 54 cuttingperipheral 2 51 cutting peripheral parting 2 65 cutting polyolefin 2 33cutting steps 2 60 cutting excess 2 79 density ft 2 65 density greaterdensity 2 79 density lb 2 65 density method 4 55 density polyolefin 2 33density density 2 51 excess ft 2 65 excess lb 2 65 excess method 2 30excess cavity 3 60 forming cutting 2 79 forming forming cavity 2 79forming method 3 45 forming method for forming 3 89 forming parting 3 71forming peripheral 3 69 forming peripheral parting 2 65 formingpolyolefin 3 49 forming steps 3 78 forming cavity 2 43 forming cavitycutting 2 79 forming cavity forming 2 60 forming cavity method 2 30forming cavity method for forming 2 71 forming cavity parting 2 54forming cavity peripheral 2 51 forming cavity peripheral parting 2 65forming cavity polyolefin 2 33 forming cavity steps 2 60 forming cavitydensity 2 51 ft excess 2 79 ft lb 2 65 ft method 2 30 ft density 2 51greater density method 2 30 greater density polyolefin 2 33 greaterdensity cavity 5 79 heating closing 4 86 heating method 7 74 heatingparting 4 82 heating peripheral 2 51 heating peripheral parting 2 65heating polyolefin 4 59 heating sufficient 9 93 heating sufficientperiod 3 89 heating sufficient temperature 6 100 heating temperature 898 heating density 2 51 lb excess 2 79 lb ft 2 65 lb method 2 30 lbcarrie integral fastening 2 79 method means cavity 4 71 method cutting 279 method density 4 79 method excess 2 79 method forming 3 78 methodforming cavity 2 79 method ft 2 65 method greater density 2 79 methodheating 7 87 method lb 2 65 method method for forming 3 89 methodnonfoamed 2 79 method organic polymer 2 79 method parting 4 82 methodperipheral 3 69 method peripheral parting 2 65 method polyethylene 2 79method polyolefin 9 86 method steps 5 97 method sufficient 6 80 methodsufficient temperature 6 100 method temperature 8 98 method cavity 3 60method for forming cutting 2 79 method for forming forming 3 78 methodfor forming forming cavity 2 79 method for forming method 3 45 methodfor forming parting 3 71 method for forming peripheral 3 69 method forforming peripheral parting 2 65 method for forming polyolefin 3 49method for forming steps 3 78 method for forming method 2 30 nonfoamedorganic polymer 2 79 nonfoamed method 2 30 organic polymer nonfoamed 279 organic polymer cavity 5 79 parting closing 3 75 parting cutting 2 79parting forming 3 78 parting forming cavity 2 79 parting heating 4 68parting method 4 55 parting method for forming 3 89 parting peripheral 587 parting peripheral parting 4 94 parting polyolefin 5 67 partingpolyolefin being 2 79 parting steps 3 78 parting temperature 3 64parting cavity 5 79 peripheral closing 2 57 peripheral cutting 2 79peripheral forming 3 78 peripheral forming cavity 2 79 peripheralheating 2 40 peripheral method 3 45 peripheral method for forming 3 89peripheral parting 5 90 peripheral peripheral parting 4 94 peripheralpolyolefin 3 49 peripheral steps 3 78 peripheral temperature 3 64peripheral cavity 4 71 peripheral parting closing 2 57 peripheralparting cutting 2 79 peripheral parting forming 2 60 peripheral partingforming cavity 2 79 peripheral parting heating 2 40 peripheral partingmethod 2 30 peripheral parting method for forming 2 71 peripheralparting parting 4 82 peripheral parting peripheral 4 79 peripheralparting polyolefin 2 33 peripheral parting steps 2 60 peripheral partingtemperature 2 47 peripheral parting method 2 30 polyethylene polyolefin2 33 polyethylene cavity 6 85 polyolefin cutting 2 79 polyolefin density2 51 polyolefin forming 3 78 polyolefin forming cavity 2 79 polyolefingreater density 2 79 polyolefin heating 4 68 polyolefin method 9 81polyolefin method for forming 3 89 polyolefin parting 5 90 polyolefinperipheral 3 69 polyolefin peripheral parting 2 65 polyolefinpolyethylene 2 79 polyolefin polyolefin being 2 79 polyolefin steps 4 89polyolefin temperature 2 47 polyolefin parting 2 54 polyolefin beingpolyolefin 2 33 polyolefin being cavity 4 71 steps cutting 2 79 stepsforming 3 78 steps forming cavity 2 79 steps method 5 63 steps methodfor forming 3 89 steps parting 3 71 steps peripheral 3 69 stepsperipheral parting 2 65 steps polyolefin 4 59 steps temperature 3 64steps cavity 2 43 sufficient heating 9 95 sufficient method 6 69sufficient sufficient period 3 89 sufficient sufficient temperature 6100 sufficient temperature 6 89 sufficient cavity 2 43 sufficient periodheating 3 57 sufficient period sufficient 3 56 sufficient period heating6 82 sufficient temperature method 6 69 sufficient temperaturesufficient 6 80 sufficient temperature temperature 6 89 sufficienttemperature cavity 4 71 temperature closing 2 57 temperature heating 891 temperature method 8 78 temperature parting 3 71 temperatureperipheral 3 69 temperature peripheral parting 2 65 temperaturepolyolefin 2 33 temperature steps 3 78 temperature sufficient 6 80temperature sufficient temperature 6 100 temperature

APPENDIX V

D. Data for Appendix III, U.S. Pat. No. 4,595,551 (CitedReference—Maurer)

(1) Data Used in

Exemplary Semantic

Analysis Concept Weight copolymer 29 decorative fabric 14 fabric 43facing 53 heating 6 method 90 Means outer 66 peripheral polymer 49impregnated polystyrene 22 polyurethane 72 styrene 29 styrenic 86Plastic polyolefin temperature 69 thermoforming 7 forming

(2) Composite and Specific Frequency/Weight Data Parent Frequency WeightSubordinate copolymer 2 29 ========== decorative fabric 2 14 ==========fabric 6 43 ========== facing 4 53 ========== heating 2 6 ==========method 15 90 ========== outer 7 66 ========== polymer 2 49 ==========impregnated polystyrene 2 22 ========== polyurethane 9 72 ==========styrene 2 29 ========== styrenic 17 86 ========== temperature 7 69========== thermoforming 3 7 ========== method 2 37 copolymer styrene 277 copolymer styrenic 2 35 copolymer fabric 2 55 decorative fabricmethod 2 37 decorative fabric decorative fabric 2 77 fabric facing 3 81fabric method 4 64 fabric polymer 2 77 fabric impregnated styrenic 2 35fabric fabric 3 72 facing method 4 64 facing polymer 2 77 facingimpregnated styrenic 3 51 facing temperature 2 52 heating copolymer 2 77method decorative fabric 2 77 method fabric 4 83 method facing 4 92method outer 4 80 method polymer 2 77 method impregnated polystyrene 277 method polyurethane 6 89 method styrene 2 77 method styrenic 12 97method temperature 4 80 method method 4 64 outer polyurethane 5 83 outerstyrenic 4 62 outer temperature 3 69 outer fabric 2 55 polymerimpregnated facing 2 63 polymer impregnated method 2 37 polymerimpregnated styrenic 2 35 polymer impregnated method 2 37 polystyrenestyrenic 2 35 polystyrene method 6 78 polyurethane outer 5 88polyurethane styrenic 6 75 polyurethane temperature 5 88 polyurethanecopolymer 2 77 styrene method 2 37 styrene styrenic 2 35 styrenecopolymer 2 77 styrenic fabric 2 55 styrenic facing 3 81 styrenic method12 100 styrenic outer 4 80 styrenic polymer 2 77 styrenic impregnatedpolystyrene 2 77 styrenic polyurethane 6 89 styrenic styrene 2 77styrenic temperature 5 88 styrenic thermoforming 2 69 styrenic heating 277 temperature method 4 64 temperature outer 3 69 temperaturepolyurethane 5 83 temperature styrenic 5 69 temperature styrenic 2 35thermoforming

APPENDIX V

E. Data for Appendix IVA—U.S. Pat. No. 4,627,177 (Control 1)

(1) Data Used in Exemplary

Semantic Analysis Concept Weight material 98 member 95

(2) Composite and Specific Frequency/Weight Data Parent Frequency WeightSubordinate material 4 98 ========== material 3 100 member member 9 95========== member 3 82 material

APPENDIX V

F. Data for Appendix IVB—U.S. Pat. No. 4,364,189 (Control 2)

(1) Data Used in Exemplary

Semantic Analysis Concept Weight absorbing 69 density 9 elastomeric 10firmness 86 lateral 62 longitudinal 86 means 49 midline axis 70operative 6 outer 77 resilient material 86 Plastic stability 69 used forrunning 69

(2) Composite and Specific Frequency/Weight Data Concept FrequencyWeight Subordinate Concept absorbing 2 69 ========== density 3 9========== elastomeric 2 10 ========== firmness 2 86 ========== lateral3 62 ========== longitudinal 2 86 ========== means 7 49 ==========midline axis 7 70 ========== operative 2 6 ========== outer 4 77========== resilient 2 86 ========== material stability 2 69 ==========used for 2 69 ========== running lateral 2 91 absorbing means 2 73absorbing stability 2 100 absorbing used for 2 100 absorbing runningelastomeric 2 100 density midline axis 2 73 density density 2 91elastomeric midline axis 2 73 elastomeric longitudinal 2 100 firmnessmidline axis 2 73 firmness outer 2 85 firmness resilient 2 100 firmnessmaterial absorbing 2 100 lateral means 2 73 lateral stability 2 100lateral used for 2 100 lateral running firmness 2 100 longitudinalmidline axis 2 73 longitudinal outer 2 85 longitudinal resilient 2 100longitudinal material absorbing 2 100 means lateral 2 91 means operative2 100 means stability 2 100 means used for 2 100 means running density 291 midline axis elastomeric 2 100 midline axis firmness 2 100 midlineaxis longitudinal 2 100 midline axis outer 2 85 midline axis resilient 2100 midline axis material means 2 73 operative firmness 2 100 outerlongitudinal 2 100 outer midline axis 2 73 outer resilient 2 100 outermaterial firmness 2 100 resilient material longitudinal 2 100 resilientmaterial midline axis 2 73 resilient material outer 2 85 resilientmaterial absorbing 2 100 stability lateral 2 91 stability means 2 73stability used for 2 100 stability running absorbing 2 100 used forrunning lateral 2 91 used for running means 2 73 used for runningstability 2 100 used for running

Modifications and substitutions by one of ordinary skill in the art,such as, for example, utilizing various semantic analysis methodologiesto extract a document's semantic content, storing the semantic contentin a variety of output formats, or using various metrics to determinethe semantic distance of two documents, are considered to be within thescope of the present invention, which is not to be limited except by theclaims which follow at the end of this application.

1. A method of comparing the semantic content of two or more documents,comprising: accessing two or more documents; performing a linguisticanalysis on each document; outputting a quantified representation of thesemantic content of each document; and comparing the quantifiedrepresentations using a defined algorithm.
 2. The method of claim 1,wherein the linguistic analysis comprises sentence analysis.
 3. Themethod of claim 2, wherein the sentence analysis comprises a syntacticanalysis and a semantic analysis.
 4. The method of claim 1 wherein thequantified representation of a semantic content is a semantic vector. 5.The method of claim 4, wherein the semantic vector can have multiplecomponents.
 6. The method of claim 5, wherein each component can havemultiple dimensions.
 7. The method of claim 6, wherein each component ofthe semantic vector includes one or more text values.
 8. The method ofclaim 7, wherein each text value can have one or more numerical valuesassociated with it.
 9. The method of claim 8, wherein each component ofthe semantic vector has three values: a word or phrase appearing in thedocument or a synonym of said word or phrase; a weighting factorassociated with said word or phrase or synonym; and a frequency value.10. The method of claim 8 wherein each component of the semantic vectorhas two values: a word or phrase appearing in the document or a synonymof said word or phrase; and a weighting factor associated with that wordor phrase.
 11. The method of claim 4, wherein the semantic vector is amulti-dimensional vector defined by the content of a semantic net. 12.The method of claim 11, wherein the content of the semantic net isaugmented by relative weights, strengths, or frequencies of occurrenceof the features within the semantic net.
 13. The method of claim 1,wherein the output of said defined algorithm is a measure of at leastone of semantic distance, semantic similarity, semantic dissimilarity,degree of patentable novelty and degree of anticipation.
 14. A method ofcomparing two or more documents, comprising: linguistically analyzingtwo or more documents; generating a semantic vector associated with eachdocument; and comparing the semantic vectors using a defined metric. 15.The method of claim 14, wherein said defined metric is one of:${\frac{{Sqrt}\left( {{f\quad 1^{2}} + {f\quad 2^{2}} + {f\quad 3^{2}} + {f\quad 4^{2}} + \quad{{+ {f\left( {N - 1} \right)}^{2}}f\quad N^{2}}} \right)}{n}*100},$wherein f is a difference in frequency of a common term between twodocuments and n is the number of terms those documents have in common;orSqrt(sum((w−Delta)A2*w−Avg))/(Log(n)A3*1000), wherein w-Delta is thedifference in weight between two common terms, w-Avg is the averageweight between two common terms, and n is the number of common terms,between two documents.
 16. The method of claim 15, wherein a common termbetween two documents includes two terms that are synonyms.
 17. Themethod of claim 14, wherein one or more of said two or more documentsare located using an autonomous software or 'bot program.
 18. The methodof claim 17, wherein the 'bot program: automatically analyzes eachdocument in a defined domain or network by executing a series of rulesand assigning an overall score to the document.
 19. The method of claim18, wherein all documents with a score above a defined threshold arelinguistically analyzed.
 20. The method of claim 14, wherein thesemantic vector is a quantification of the semantic content of eachdocument.
 21. The method of claim 14, wherein the semantic vector canhave multiple components, and each component can have multipledimensions.
 22. The method of claim 14, wherein each component of thesemantic vector has a word or phrase appearing in the document or asynonym of said word or phrase; and at least one of a weighting factorassociated with said word or phrase or synonym and a frequency value.23. A system for comparing two or more documents, comprising: a documentinputter, arranged to access two or more documents; a semantic analyzer,arranged to perform a linguistic analysis on each document; a semanticquantifier, arranged to output a quantified representation of a semanticcontent of each document; and a comparator, arranged to compare thequantified representations using a defined algorithm.
 24. A system forcomparing two or more documents, comprising: a document inputter,arranged to access two or more documents; a semantic analyzer, arrangedto perform a linguistic analysis on each document; a semantic vectorgenerator, arranged to output a semantic vector associated with eachdocument; and a comparator, arranged to compare the semantic vectorsusing a defined metric.
 25. The system of claim 24, wherein said definedmetric is one of:${\frac{{Sqrt}\left( {{f\quad 1^{2}} + {f\quad 2^{2}} + {f\quad 3^{2}} + {f\quad 4^{2}} + \quad{{+ {f\left( {N - 1} \right)}^{2}}f\quad N^{2}}} \right)}{n}*100},$wherein f is a difference in frequency of a common term between twodocuments and n is the number of terms those documents have in common;orSqrt(sum((w−Delta)A2*w−Avg))/(Log(n)A3*1000), wherein w-Delta is thedifference in weight between two common terms, w-Avg is the averageweight between two common terms, and n is the number of common terms,between two documents.
 26. A computer program product comprising acomputer usable medium having computer readable program code meansembodied therein, the computer readable program code means in saidcomputer program product comprising means for causing a computer to:access two or more documents; perform a linguistic analysis on eachdocument; output a quantified representation of a semantic content ofeach document; and compare the quantified representations using adefined algorithm.
 27. A computer program product comprising a computerusable medium having computer readable program code means embodiedtherein, the computer readable program code means in said computerprogram product comprising means for causing a computer to:linguistically analyzing two or more documents; generating a semanticvector associated with each document; and comparing the semantic vectorsusing a defined metric.
 28. The computer program product of claim 27,wherein the computer readable program code means in said computerprogram product further comprises means for causing a computer to:identify one or more of said two or more documents using an autonomoussoftware or 'bot program.
 29. The computer program product of claim 27,wherein said 'bot program automatically analyzes each document in adefined domain or network by executing a series of rules and assigningan overall score to the document.
 30. The computer program product ofclaim 27, wherein the semantic vector is a quantification of thesemantic content of each document.
 31. The computer program product ofclaim 27, wherein the output of said defined metric is a measure of atleast one of semantic distance, semantic similarity, semanticdissimilarity, degree of patentable novelty and degree of anticipation.32. The computer program product of claim 27, wherein said definedmetric is one of:${\frac{{Sqrt}\left( {{f\quad 1^{2}} + {f\quad 2^{2}} + {f\quad 3^{2}} + {f\quad 4^{2}} + \quad{{+ {f\left( {N - 1} \right)}^{2}}f\quad N^{2}}} \right)}{n}*100},$wherein f is a difference in frequency of a common term between twodocuments and n is the number of terms those documents have in common;orSqrt(sum((w−Delta)A2*w−Avg))/(Log(n)A3*1000), wherein w-Delta is thedifference in weight between two common terms, w-Avg is the averageweight between two common terms, and n is the number of common terms,between two documents.